58 files changed, 3506 insertions, 2941 deletions

diff --git a/Documentation/filesystems/caching/fscache.txt b/Documentation/filesystems/caching/fscache.txt
index a91e2e2095b0..770267af5b3e 100644
--- a/Documentation/filesystems/caching/fscache.txt
+++ b/Documentation/filesystems/caching/fscache.txt
@@ -343,8 +343,8 @@ This will look something like:
         [root@andromeda ~]# head /proc/fs/fscache/objects
         OBJECT   PARENT   STAT CHLDN OPS OOP IPR EX READS EM EV F S | NETFS_COOKIE_DEF TY FL NETFS_DATA       OBJECT_KEY, AUX_DATA
         ======== ======== ==== ===== === === === == ===== == == = = | ================ == == ================ ================
-           17e4b        2 ACTV     0   0   0   0  0     0 7b  4 0 8 | NFS.fh           DT  0 ffff88001dd82820 010006017edcf8bbc93b43298fdfbe71e50b57b13a172c0117f38472, e567634700000000000000000000000063f2404a000000000000000000000000c9030000000000000000000063f2404a
-           1693a        2 ACTV     0   0   0   0  0     0 7b  4 0 8 | NFS.fh           DT  0 ffff88002db23380 010006017edcf8bbc93b43298fdfbe71e50b57b1e0162c01a2df0ea6, 420ebc4a000000000000000000000000420ebc4a0000000000000000000000000e1801000000000000000000420ebc4a
+           17e4b        2 ACTV     0   0   0   0  0     0 7b  4 0 0 | NFS.fh           DT  0 ffff88001dd82820 010006017edcf8bbc93b43298fdfbe71e50b57b13a172c0117f38472, e567634700000000000000000000000063f2404a000000000000000000000000c9030000000000000000000063f2404a
+           1693a        2 ACTV     0   0   0   0  0     0 7b  4 0 0 | NFS.fh           DT  0 ffff88002db23380 010006017edcf8bbc93b43298fdfbe71e50b57b1e0162c01a2df0ea6, 420ebc4a000000000000000000000000420ebc4a0000000000000000000000000e1801000000000000000000420ebc4a
 
 where the first set of columns before the '|' describe the object:
 
@@ -362,7 +362,7 @@ where the first set of columns before the '|' describe the object:
         EM      Object's event mask
         EV      Events raised on this object
         F       Object flags
-        S       Object slow-work work item flags
+        S       Object work item busy state mask (1:pending 2:running)
 
 and the second set of columns describe the object's cookie, if present:
 
@@ -395,8 +395,8 @@ and the following paired letters:
         w       Show objects that don't have pending writes
         R       Show objects that have outstanding reads
         r       Show objects that don't have outstanding reads
-        S       Show objects that have slow work queued
-        s       Show objects that don't have slow work queued
+        S       Show objects that have work queued
+        s       Show objects that don't have work queued
 
 If neither side of a letter pair is given, then both are implied.  For example:
 
diff --git a/Documentation/slow-work.txt b/Documentation/slow-work.txt
deleted file mode 100644
index 9dbf4470c7e1..000000000000
--- a/Documentation/slow-work.txt
+++ /dev/null
@@ -1,322 +0,0 @@
-                     ====================================
-                     SLOW WORK ITEM EXECUTION THREAD POOL
-                     ====================================
-
-By: David Howells <dhowells@redhat.com>
-
-The slow work item execution thread pool is a pool of threads for performing
-things that take a relatively long time, such as making mkdir calls.
-Typically, when processing something, these items will spend a lot of time
-blocking a thread on I/O, thus making that thread unavailable for doing other
-work.
-
-The standard workqueue model is unsuitable for this class of work item as that
-limits the owner to a single thread or a single thread per CPU.  For some
-tasks, however, more threads - or fewer - are required.
-
-There is just one pool per system.  It contains no threads unless something
-wants to use it - and that something must register its interest first.  When
-the pool is active, the number of threads it contains is dynamic, varying
-between a maximum and minimum setting, depending on the load.
-
-
-====================
-CLASSES OF WORK ITEM
-====================
-
-This pool support two classes of work items:
-
- (*) Slow work items.
-
- (*) Very slow work items.
-
-The former are expected to finish much quicker than the latter.
-
-An operation of the very slow class may do a batch combination of several
-lookups, mkdirs, and a create for instance.
-
-An operation of the ordinarily slow class may, for example, write stuff or
-expand files, provided the time taken to do so isn't too long.
-
-Operations of both types may sleep during execution, thus tying up the thread
-loaned to it.
-
-A further class of work item is available, based on the slow work item class:
-
- (*) Delayed slow work items.
-
-These are slow work items that have a timer to defer queueing of the item for
-a while.
-
-
-THREAD-TO-CLASS ALLOCATION
---------------------------
-
-Not all the threads in the pool are available to work on very slow work items.
-The number will be between one and one fewer than the number of active threads.
-This is configurable (see the "Pool Configuration" section).
-
-All the threads are available to work on ordinarily slow work items, but a
-percentage of the threads will prefer to work on very slow work items.
-
-The configuration ensures that at least one thread will be available to work on
-very slow work items, and at least one thread will be available that won't work
-on very slow work items at all.
-
-
-=====================
-USING SLOW WORK ITEMS
-=====================
-
-Firstly, a module or subsystem wanting to make use of slow work items must
-register its interest:
-
-         int ret = slow_work_register_user(struct module *module);
-
-This will return 0 if successful, or a -ve error upon failure.  The module
-pointer should be the module interested in using this facility (almost
-certainly THIS_MODULE).
-
-
-Slow work items may then be set up by:
-
- (1) Declaring a slow_work struct type variable:
-
-        #include <linux/slow-work.h>
-
-        struct slow_work myitem;
-
- (2) Declaring the operations to be used for this item:
-
-        struct slow_work_ops myitem_ops = {
-                .get_ref = myitem_get_ref,
-                .put_ref = myitem_put_ref,
-                .execute = myitem_execute,
-        };
-
-     [*] For a description of the ops, see section "Item Operations".
-
- (3) Initialising the item:
-
-        slow_work_init(&myitem, &myitem_ops);
-
-     or:
-
-        delayed_slow_work_init(&myitem, &myitem_ops);
-
-     or:
-
-        vslow_work_init(&myitem, &myitem_ops);
-
-     depending on its class.
-
-A suitably set up work item can then be enqueued for processing:
-
-        int ret = slow_work_enqueue(&myitem);
-
-This will return a -ve error if the thread pool is unable to gain a reference
-on the item, 0 otherwise, or (for delayed work):
-
-        int ret = delayed_slow_work_enqueue(&myitem, my_jiffy_delay);
-
-
-The items are reference counted, so there ought to be no need for a flush
-operation.  But as the reference counting is optional, means to cancel
-existing work items are also included:
-
-        cancel_slow_work(&myitem);
-        cancel_delayed_slow_work(&myitem);
-
-can be used to cancel pending work.  The above cancel function waits for
-existing work to have been executed (or prevent execution of them, depending
-on timing).
-
-
-When all a module's slow work items have been processed, and the
-module has no further interest in the facility, it should unregister its
-interest:
-
-        slow_work_unregister_user(struct module *module);
-
-The module pointer is used to wait for all outstanding work items for that
-module before completing the unregistration.  This prevents the put_ref() code
-from being taken away before it completes.  module should almost certainly be
-THIS_MODULE.
-
-
-================
-HELPER FUNCTIONS
-================
-
-The slow-work facility provides a function by which it can be determined
-whether or not an item is queued for later execution:
-
-        bool queued = slow_work_is_queued(struct slow_work *work);
-
-If it returns false, then the item is not on the queue (it may be executing
-with a requeue pending).  This can be used to work out whether an item on which
-another depends is on the queue, thus allowing a dependent item to be queued
-after it.
-
-If the above shows an item on which another depends not to be queued, then the
-owner of the dependent item might need to wait.  However, to avoid locking up
-the threads unnecessarily be sleeping in them, it can make sense under some
-circumstances to return the work item to the queue, thus deferring it until
-some other items have had a chance to make use of the yielded thread.
-
-To yield a thread and defer an item, the work function should simply enqueue
-the work item again and return.  However, this doesn't work if there's nothing
-actually on the queue, as the thread just vacated will jump straight back into
-the item's work function, thus busy waiting on a CPU.
-
-Instead, the item should use the thread to wait for the dependency to go away,
-but rather than using schedule() or schedule_timeout() to sleep, it should use
-the following function:
-
-        bool requeue = slow_work_sleep_till_thread_needed(
-                        struct slow_work *work,
-                        signed long *_timeout);
-
-This will add a second wait and then sleep, such that it will be woken up if
-either something appears on the queue that could usefully make use of the
-thread - and behind which this item can be queued, or if the event the caller
-set up to wait for happens.  True will be returned if something else appeared
-on the queue and this work function should perhaps return, of false if
-something else woke it up.  The timeout is as for schedule_timeout().
-
-For example:
-
-        wq = bit_waitqueue(&my_flags, MY_BIT);
-        init_wait(&wait);
-        requeue = false;
-        do {
-                prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
-                if (!test_bit(MY_BIT, &my_flags))
-                        break;
-                requeue = slow_work_sleep_till_thread_needed(&my_work,
-                                                             &timeout);
-        } while (timeout > 0 && !requeue);
-        finish_wait(wq, &wait);
-        if (!test_bit(MY_BIT, &my_flags)
-                goto do_my_thing;
-        if (requeue)
-                return; // to slow_work
-
-
-===============
-ITEM OPERATIONS
-===============
-
-Each work item requires a table of operations of type struct slow_work_ops.
-Only ->execute() is required; the getting and putting of a reference and the
-describing of an item are all optional.
-
- (*) Get a reference on an item:
-
-        int (*get_ref)(struct slow_work *work);
-
-     This allows the thread pool to attempt to pin an item by getting a
-     reference on it.  This function should return 0 if the reference was
-     granted, or a -ve error otherwise.  If an error is returned,
-     slow_work_enqueue() will fail.
-
-     The reference is held whilst the item is queued and whilst it is being
-     executed.  The item may then be requeued with the same reference held, or
-     the reference will be released.
-
- (*) Release a reference on an item:
-
-        void (*put_ref)(struct slow_work *work);
-
-     This allows the thread pool to unpin an item by releasing the reference on
-     it.  The thread pool will not touch the item again once this has been
-     called.
-
- (*) Execute an item:
-
-        void (*execute)(struct slow_work *work);
-
-     This should perform the work required of the item.  It may sleep, it may
-     perform disk I/O and it may wait for locks.
-
- (*) View an item through /proc:
-
-        void (*desc)(struct slow_work *work, struct seq_file *m);
-
-     If supplied, this should print to 'm' a small string describing the work
-     the item is to do.  This should be no more than about 40 characters, and
-     shouldn't include a newline character.
-
-     See the 'Viewing executing and queued items' section below.
-
-
-==================
-POOL CONFIGURATION
-==================
-
-The slow-work thread pool has a number of configurables:
-
- (*) /proc/sys/kernel/slow-work/min-threads
-
-     The minimum number of threads that should be in the pool whilst it is in
-     use.  This may be anywhere between 2 and max-threads.
-
- (*) /proc/sys/kernel/slow-work/max-threads
-
-     The maximum number of threads that should in the pool.  This may be
-     anywhere between min-threads and 255 or NR_CPUS * 2, whichever is greater.
-
- (*) /proc/sys/kernel/slow-work/vslow-percentage
-
-     The percentage of active threads in the pool that may be used to execute
-     very slow work items.  This may be between 1 and 99.  The resultant number
-     is bounded to between 1 and one fewer than the number of active threads.
-     This ensures there is always at least one thread that can process very
-     slow work items, and always at least one thread that won't.
-
-
-==================================
-VIEWING EXECUTING AND QUEUED ITEMS
-==================================
-
-If CONFIG_SLOW_WORK_DEBUG is enabled, a debugfs file is made available:
-
-        /sys/kernel/debug/slow_work/runqueue
-
-through which the list of work items being executed and the queues of items to
-be executed may be viewed.  The owner of a work item is given the chance to
-add some information of its own.
-
-The contents look something like the following:
-
-    THR PID   ITEM ADDR        FL MARK  DESC
-    === ===== ================ == ===== ==========
-      0  3005 ffff880023f52348  a 952ms FSC: OBJ17d3: LOOK
-      1  3006 ffff880024e33668  2 160ms FSC: OBJ17e5 OP60d3b: Write1/Store fl=2
-      2  3165 ffff8800296dd180  a 424ms FSC: OBJ17e4: LOOK
-      3  4089 ffff8800262c8d78  a 212ms FSC: OBJ17ea: CRTN
-      4  4090 ffff88002792bed8  2 388ms FSC: OBJ17e8 OP60d36: Write1/Store fl=2
-      5  4092 ffff88002a0ef308  2 388ms FSC: OBJ17e7 OP60d2e: Write1/Store fl=2
-      6  4094 ffff88002abaf4b8  2 132ms FSC: OBJ17e2 OP60d4e: Write1/Store fl=2
-      7  4095 ffff88002bb188e0  a 388ms FSC: OBJ17e9: CRTN
-    vsq     - ffff880023d99668  1 308ms FSC: OBJ17e0 OP60f91: Write1/EnQ fl=2
-    vsq     - ffff8800295d1740  1 212ms FSC: OBJ16be OP4d4b6: Write1/EnQ fl=2
-    vsq     - ffff880025ba3308  1 160ms FSC: OBJ179a OP58dec: Write1/EnQ fl=2
-    vsq     - ffff880024ec83e0  1 160ms FSC: OBJ17ae OP599f2: Write1/EnQ fl=2
-    vsq     - ffff880026618e00  1 160ms FSC: OBJ17e6 OP60d33: Write1/EnQ fl=2
-    vsq     - ffff880025a2a4b8  1 132ms FSC: OBJ16a2 OP4d583: Write1/EnQ fl=2
-    vsq     - ffff880023cbe6d8  9 212ms FSC: OBJ17eb: LOOK
-    vsq     - ffff880024d37590  9 212ms FSC: OBJ17ec: LOOK
-    vsq     - ffff880027746cb0  9 212ms FSC: OBJ17ed: LOOK
-    vsq     - ffff880024d37ae8  9 212ms FSC: OBJ17ee: LOOK
-    vsq     - ffff880024d37cb0  9 212ms FSC: OBJ17ef: LOOK
-    vsq     - ffff880025036550  9 212ms FSC: OBJ17f0: LOOK
-    vsq     - ffff8800250368e0  9 212ms FSC: OBJ17f1: LOOK
-    vsq     - ffff880025036aa8  9 212ms FSC: OBJ17f2: LOOK
-
-In the 'THR' column, executing items show the thread they're occupying and
-queued threads indicate which queue they're on.  'PID' shows the process ID of
-a slow-work thread that's executing something.  'FL' shows the work item flags.
-'MARK' indicates how long since an item was queued or began executing.  Lastly,
-the 'DESC' column permits the owner of an item to give some information.
-
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 6a1380e90f87..99dcc85193c9 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -519,7 +519,7 @@ do_boot_cpu (int sapicid, int cpu)
         /*
          * We can't use kernel_thread since we must avoid to reschedule the child.
          */
-        if (!keventd_up() || current_is_keventd())
+        if (!keventd_up())
                 c_idle.work.func(&c_idle.work);
         else {
                 schedule_work(&c_idle.work);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 11015fd1abbc..51620953b18a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -735,7 +735,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
                 goto do_rest;
         }
 
-        if (!keventd_up() || current_is_keventd())
+        if (!keventd_up())
                 c_idle.work.func(&c_idle.work);
         else {
                 schedule_work(&c_idle.work);
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 78418ce4fc78..46cce391fa46 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -191,36 +191,11 @@ acpi_status __init acpi_os_initialize(void)
         return AE_OK;
 }
 
-static void bind_to_cpu0(struct work_struct *work)
-{
-        set_cpus_allowed_ptr(current, cpumask_of(0));
-        kfree(work);
-}
-
-static void bind_workqueue(struct workqueue_struct *wq)
-{
-        struct work_struct *work;
-
-        work = kzalloc(sizeof(struct work_struct), GFP_KERNEL);
-        INIT_WORK(work, bind_to_cpu0);
-        queue_work(wq, work);
-}
-
 acpi_status acpi_os_initialize1(void)
 {
-        /*
-         * On some machines, a software-initiated SMI causes corruption unless
-         * the SMI runs on CPU 0.  An SMI can be initiated by any AML, but
-         * typically it's done in GPE-related methods that are run via
-         * workqueues, so we can avoid the known corruption cases by binding
-         * the workqueues to CPU 0.
-         */
-        kacpid_wq = create_singlethread_workqueue("kacpid");
-        bind_workqueue(kacpid_wq);
-        kacpi_notify_wq = create_singlethread_workqueue("kacpi_notify");
-        bind_workqueue(kacpi_notify_wq);
-        kacpi_hotplug_wq = create_singlethread_workqueue("kacpi_hotplug");
-        bind_workqueue(kacpi_hotplug_wq);
+        kacpid_wq = create_workqueue("kacpid");
+        kacpi_notify_wq = create_workqueue("kacpi_notify");
+        kacpi_hotplug_wq = create_workqueue("kacpi_hotplug");
         BUG_ON(!kacpid_wq);
         BUG_ON(!kacpi_notify_wq);
         BUG_ON(!kacpi_hotplug_wq);
@@ -766,7 +741,14 @@ static acpi_status __acpi_os_execute(acpi_execute_type type,
         else
                 INIT_WORK(&dpc->work, acpi_os_execute_deferred);
 
-        ret = queue_work(queue, &dpc->work);
+        /*
+         * On some machines, a software-initiated SMI causes corruption unless
+         * the SMI runs on CPU 0.  An SMI can be initiated by any AML, but
+         * typically it's done in GPE-related methods that are run via
+         * workqueues, so we can avoid the known corruption cases by always
+         * queueing on CPU 0.
+         */
+        ret = queue_work_on(0, queue, &dpc->work);
 
         if (!ret) {
                 printk(KERN_ERR PREFIX
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index a0a4d6968400..4972fdf4bd31 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -98,8 +98,6 @@ static unsigned long ata_dev_blacklisted(const struct ata_device *dev);
 
 unsigned int ata_print_id = 1;
 
-struct workqueue_struct *ata_aux_wq;
-
 struct ata_force_param {
         const char      *name;
         unsigned int    cbl;
@@ -5594,6 +5592,7 @@ struct ata_port *ata_port_alloc(struct ata_host *host)
         ap->msg_enable = ATA_MSG_DRV | ATA_MSG_ERR | ATA_MSG_WARN;
 #endif
 
+        mutex_init(&ap->scsi_scan_mutex);
         INIT_DELAYED_WORK(&ap->hotplug_task, ata_scsi_hotplug);
         INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan);
         INIT_LIST_HEAD(&ap->eh_done_q);
@@ -6532,29 +6531,20 @@ static int __init ata_init(void)
 
         ata_parse_force_param();
 
-        ata_aux_wq = create_singlethread_workqueue("ata_aux");
-        if (!ata_aux_wq)
-                goto fail;
-
         rc = ata_sff_init();
-        if (rc)
-                goto fail;
+        if (rc) {
+                kfree(ata_force_tbl);
+                return rc;
+        }
 
         printk(KERN_DEBUG "libata version " DRV_VERSION " loaded.\n");
         return 0;
-
-fail:
-        kfree(ata_force_tbl);
-        if (ata_aux_wq)
-                destroy_workqueue(ata_aux_wq);
-        return rc;
 }
 
 static void __exit ata_exit(void)
 {
         ata_sff_exit();
         kfree(ata_force_tbl);
-        destroy_workqueue(ata_aux_wq);
 }
 
 subsys_initcall(ata_init);
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 697474b625b7..c9ae299b8342 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -727,7 +727,7 @@ void ata_scsi_error(struct Scsi_Host *host)
         if (ap->pflags & ATA_PFLAG_LOADING)
                 ap->pflags &= ~ATA_PFLAG_LOADING;
         else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
-                queue_delayed_work(ata_aux_wq, &ap->hotplug_task, 0);
+                schedule_delayed_work(&ap->hotplug_task, 0);
 
         if (ap->pflags & ATA_PFLAG_RECOVERED)
                 ata_port_printk(ap, KERN_INFO, "EH complete\n");
@@ -2945,7 +2945,7 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
                         ehc->i.flags |= ATA_EHI_SETMODE;
 
                         /* schedule the scsi_rescan_device() here */
-                        queue_work(ata_aux_wq, &(ap->scsi_rescan_task));
+                        schedule_work(&(ap->scsi_rescan_task));
                 } else if (dev->class == ATA_DEV_UNKNOWN &&
                            ehc->tries[dev->devno] &&
                            ata_class_enabled(ehc->classes[dev->devno])) {
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index a54273d2c3c6..d75c9c479d1a 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3435,7 +3435,7 @@ void ata_scsi_scan_host(struct ata_port *ap, int sync)
                                 "                  switching to async\n");
         }
 
-        queue_delayed_work(ata_aux_wq, &ap->hotplug_task,
+        queue_delayed_work(system_long_wq, &ap->hotplug_task,
                            round_jiffies_relative(HZ));
 }
 
@@ -3582,6 +3582,7 @@ void ata_scsi_hotplug(struct work_struct *work)
         }
 
         DPRINTK("ENTER\n");
+        mutex_lock(&ap->scsi_scan_mutex);
 
         /* Unplug detached devices.  We cannot use link iterator here
          * because PMP links have to be scanned even if PMP is
@@ -3595,6 +3596,7 @@ void ata_scsi_hotplug(struct work_struct *work)
         /* scan for new ones */
         ata_scsi_scan_host(ap, 0);
 
+        mutex_unlock(&ap->scsi_scan_mutex);
         DPRINTK("EXIT\n");
 }
 
@@ -3673,9 +3675,7 @@ static int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel,
  *      @work: Pointer to ATA port to perform scsi_rescan_device()
  *
  *      After ATA pass thru (SAT) commands are executed successfully,
- *      libata need to propagate the changes to SCSI layer.  This
- *      function must be executed from ata_aux_wq such that sdev
- *      attach/detach don't race with rescan.
+ *      libata need to propagate the changes to SCSI layer.
  *
  *      LOCKING:
  *      Kernel thread context (may sleep).
@@ -3688,6 +3688,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
         struct ata_device *dev;
         unsigned long flags;
 
+        mutex_lock(&ap->scsi_scan_mutex);
         spin_lock_irqsave(ap->lock, flags);
 
         ata_for_each_link(link, ap, EDGE) {
@@ -3707,6 +3708,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
         }
 
         spin_unlock_irqrestore(ap->lock, flags);
+        mutex_unlock(&ap->scsi_scan_mutex);
 }
 
 /**
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index efa4a18cfb9d..674c1436491f 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -3318,14 +3318,7 @@ void ata_sff_port_init(struct ata_port *ap)
 
 int __init ata_sff_init(void)
 {
-        /*
-         * FIXME: In UP case, there is only one workqueue thread and if you
-         * have more than one PIO device, latency is bloody awful, with
-         * occasional multi-second "hiccups" as one PIO device waits for
-         * another.  It's an ugly wart that users DO occasionally complain
-         * about; luckily most users have at most one PIO polled device.
-         */
-        ata_sff_wq = create_workqueue("ata_sff");
+        ata_sff_wq = alloc_workqueue("ata_sff", WQ_RESCUER, WQ_MAX_ACTIVE);
         if (!ata_sff_wq)
                 return -ENOMEM;
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 4b84ed60324a..9ce1ecc63e39 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -54,7 +54,6 @@ enum {
 };
 
 extern unsigned int ata_print_id;
-extern struct workqueue_struct *ata_aux_wq;
 extern int atapi_passthru16;
 extern int libata_fua;
 extern int libata_noacpi;
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 11fe9c870d17..45981304feb8 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -831,13 +831,11 @@ int drm_helper_resume_force_mode(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_helper_resume_force_mode);
 
-static struct slow_work_ops output_poll_ops;
-
 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
-static void output_poll_execute(struct slow_work *work)
+static void output_poll_execute(struct work_struct *work)
 {
-        struct delayed_slow_work *delayed_work = container_of(work, struct delayed_slow_work, work);
-        struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_slow_work);
+        struct delayed_work *delayed_work = to_delayed_work(work);
+        struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
         struct drm_connector *connector;
         enum drm_connector_status old_status, status;
         bool repoll = false, changed = false;
@@ -877,7 +875,7 @@ static void output_poll_execute(struct slow_work *work)
         }
 
         if (repoll) {
-                ret = delayed_slow_work_enqueue(delayed_work, DRM_OUTPUT_POLL_PERIOD);
+                ret = queue_delayed_work(system_nrt_wq, delayed_work, DRM_OUTPUT_POLL_PERIOD);
                 if (ret)
                         DRM_ERROR("delayed enqueue failed %d\n", ret);
         }
@@ -887,7 +885,7 @@ void drm_kms_helper_poll_disable(struct drm_device *dev)
 {
         if (!dev->mode_config.poll_enabled)
                 return;
-        delayed_slow_work_cancel(&dev->mode_config.output_poll_slow_work);
+        cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
 }
 EXPORT_SYMBOL(drm_kms_helper_poll_disable);
 
@@ -903,7 +901,7 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
         }
 
         if (poll) {
-                ret = delayed_slow_work_enqueue(&dev->mode_config.output_poll_slow_work, DRM_OUTPUT_POLL_PERIOD);
+                ret = queue_delayed_work(system_nrt_wq, &dev->mode_config.output_poll_work, DRM_OUTPUT_POLL_PERIOD);
                 if (ret)
                         DRM_ERROR("delayed enqueue failed %d\n", ret);
         }
@@ -912,9 +910,7 @@ EXPORT_SYMBOL(drm_kms_helper_poll_enable);
 
 void drm_kms_helper_poll_init(struct drm_device *dev)
 {
-        slow_work_register_user(THIS_MODULE);
-        delayed_slow_work_init(&dev->mode_config.output_poll_slow_work,
-                               &output_poll_ops);
+        INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
         dev->mode_config.poll_enabled = true;
 
         drm_kms_helper_poll_enable(dev);
@@ -924,7 +920,6 @@ EXPORT_SYMBOL(drm_kms_helper_poll_init);
 void drm_kms_helper_poll_fini(struct drm_device *dev)
 {
         drm_kms_helper_poll_disable(dev);
-        slow_work_unregister_user(THIS_MODULE);
 }
 EXPORT_SYMBOL(drm_kms_helper_poll_fini);
 
@@ -932,12 +927,8 @@ void drm_helper_hpd_irq_event(struct drm_device *dev)
 {
         if (!dev->mode_config.poll_enabled)
                 return;
-        delayed_slow_work_cancel(&dev->mode_config.output_poll_slow_work);
-        /* schedule a slow work asap */
-        delayed_slow_work_enqueue(&dev->mode_config.output_poll_slow_work, 0);
+        /* kill timer and schedule immediate execution, this doesn't block */
+        cancel_delayed_work(&dev->mode_config.output_poll_work);
+        queue_delayed_work(system_nrt_wq, &dev->mode_config.output_poll_work, 0);
 }
 EXPORT_SYMBOL(drm_helper_hpd_irq_event);
-
-static struct slow_work_ops output_poll_ops = {
-        .execute = output_poll_execute,
-};
diff --git a/drivers/media/video/ivtv/ivtv-driver.c b/drivers/media/video/ivtv/ivtv-driver.c
index 90daa6e751d8..07c5c18a25cb 100644
--- a/drivers/media/video/ivtv/ivtv-driver.c
+++ b/drivers/media/video/ivtv/ivtv-driver.c
@@ -705,6 +705,8 @@ done:
  */
 static int __devinit ivtv_init_struct1(struct ivtv *itv)
 {
+        struct sched_param param = { .sched_priority = 99 };
+
         itv->base_addr = pci_resource_start(itv->pdev, 0);
         itv->enc_mbox.max_mbox = 2; /* the encoder has 3 mailboxes (0-2) */
         itv->dec_mbox.max_mbox = 1; /* the decoder has 2 mailboxes (0-1) */
@@ -716,13 +718,17 @@ static int __devinit ivtv_init_struct1(struct ivtv *itv)
         spin_lock_init(&itv->lock);
         spin_lock_init(&itv->dma_reg_lock);
 
-        itv->irq_work_queues = create_singlethread_workqueue(itv->v4l2_dev.name);
-        if (itv->irq_work_queues == NULL) {
-                IVTV_ERR("Could not create ivtv workqueue\n");
+        init_kthread_worker(&itv->irq_worker);
+        itv->irq_worker_task = kthread_run(kthread_worker_fn, &itv->irq_worker,
+                                           itv->v4l2_dev.name);
+        if (IS_ERR(itv->irq_worker_task)) {
+                IVTV_ERR("Could not create ivtv task\n");
                 return -1;
         }
+        /* must use the FIFO scheduler as it is realtime sensitive */
+        sched_setscheduler(itv->irq_worker_task, SCHED_FIFO, &param);
 
-        INIT_WORK(&itv->irq_work_queue, ivtv_irq_work_handler);
+        init_kthread_work(&itv->irq_work, ivtv_irq_work_handler);
 
         /* start counting open_id at 1 */
         itv->open_id = 1;
@@ -1006,7 +1012,7 @@ static int __devinit ivtv_probe(struct pci_dev *pdev,
         /* PCI Device Setup */
         retval = ivtv_setup_pci(itv, pdev, pci_id);
         if (retval == -EIO)
-                goto free_workqueue;
+                goto free_worker;
         if (retval == -ENXIO)
                 goto free_mem;
 
@@ -1218,8 +1224,8 @@ free_mem:
         release_mem_region(itv->base_addr + IVTV_REG_OFFSET, IVTV_REG_SIZE);
         if (itv->has_cx23415)
                 release_mem_region(itv->base_addr + IVTV_DECODER_OFFSET, IVTV_DECODER_SIZE);
-free_workqueue:
-        destroy_workqueue(itv->irq_work_queues);
+free_worker:
+        kthread_stop(itv->irq_worker_task);
 err:
         if (retval == 0)
                 retval = -ENODEV;
@@ -1363,9 +1369,9 @@ static void ivtv_remove(struct pci_dev *pdev)
         ivtv_set_irq_mask(itv, 0xffffffff);
         del_timer_sync(&itv->dma_timer);
 
-        /* Stop all Work Queues */
-        flush_workqueue(itv->irq_work_queues);
-        destroy_workqueue(itv->irq_work_queues);
+        /* Kill irq worker */
+        flush_kthread_worker(&itv->irq_worker);
+        kthread_stop(itv->irq_worker_task);
 
         ivtv_streams_cleanup(itv, 1);
         ivtv_udma_free(itv);
diff --git a/drivers/media/video/ivtv/ivtv-driver.h b/drivers/media/video/ivtv/ivtv-driver.h
index bd084df4448a..102071246218 100644
--- a/drivers/media/video/ivtv/ivtv-driver.h
+++ b/drivers/media/video/ivtv/ivtv-driver.h
@@ -51,7 +51,7 @@
 #include <linux/unistd.h>
 #include <linux/pagemap.h>
 #include <linux/scatterlist.h>
-#include <linux/workqueue.h>
+#include <linux/kthread.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <asm/uaccess.h>
@@ -260,7 +260,6 @@ struct ivtv_mailbox_data {
 #define IVTV_F_I_DEC_PAUSED        20   /* the decoder is paused */
 #define IVTV_F_I_INITED            21   /* set after first open */
 #define IVTV_F_I_FAILED            22   /* set if first open failed */
-#define IVTV_F_I_WORK_INITED       23   /* worker thread was initialized */
 
 /* Event notifications */
 #define IVTV_F_I_EV_DEC_STOPPED    28   /* decoder stopped event */
@@ -666,8 +665,9 @@ struct ivtv {
         /* Interrupts & DMA */
         u32 irqmask;                    /* active interrupts */
         u32 irq_rr_idx;                 /* round-robin stream index */
-        struct workqueue_struct *irq_work_queues;       /* workqueue for PIO/YUV/VBI actions */
-        struct work_struct irq_work_queue;              /* work entry */
+        struct kthread_worker irq_worker;               /* kthread worker for PIO/YUV/VBI actions */
+        struct task_struct *irq_worker_task;            /* task for irq_worker */
+        struct kthread_work irq_work;   /* kthread work entry */
         spinlock_t dma_reg_lock;        /* lock access to DMA engine registers */
         int cur_dma_stream;             /* index of current stream doing DMA (-1 if none) */
         int cur_pio_stream;             /* index of current stream doing PIO (-1 if none) */
diff --git a/drivers/media/video/ivtv/ivtv-irq.c b/drivers/media/video/ivtv/ivtv-irq.c
index fea1ec33b0df..9b4faf009196 100644
--- a/drivers/media/video/ivtv/ivtv-irq.c
+++ b/drivers/media/video/ivtv/ivtv-irq.c
@@ -71,19 +71,10 @@ static void ivtv_pio_work_handler(struct ivtv *itv)
         write_reg(IVTV_IRQ_ENC_PIO_COMPLETE, 0x44);
 }
 
-void ivtv_irq_work_handler(struct work_struct *work)
+void ivtv_irq_work_handler(struct kthread_work *work)
 {
-        struct ivtv *itv = container_of(work, struct ivtv, irq_work_queue);
+        struct ivtv *itv = container_of(work, struct ivtv, irq_work);
 
-        DEFINE_WAIT(wait);
-
-        if (test_and_clear_bit(IVTV_F_I_WORK_INITED, &itv->i_flags)) {
-                struct sched_param param = { .sched_priority = 99 };
-
-                /* This thread must use the FIFO scheduler as it
-                   is realtime sensitive. */
-                sched_setscheduler(current, SCHED_FIFO, &param);
-        }
         if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_PIO, &itv->i_flags))
                 ivtv_pio_work_handler(itv);
 
@@ -975,7 +966,7 @@ irqreturn_t ivtv_irq_handler(int irq, void *dev_id)
         }
 
         if (test_and_clear_bit(IVTV_F_I_HAVE_WORK, &itv->i_flags)) {
-                queue_work(itv->irq_work_queues, &itv->irq_work_queue);
+                queue_kthread_work(&itv->irq_worker, &itv->irq_work);
         }
 
         spin_unlock(&itv->dma_reg_lock);
diff --git a/drivers/media/video/ivtv/ivtv-irq.h b/drivers/media/video/ivtv/ivtv-irq.h
index f879a5822e71..1e84433737cc 100644
--- a/drivers/media/video/ivtv/ivtv-irq.h
+++ b/drivers/media/video/ivtv/ivtv-irq.h
@@ -46,7 +46,7 @@
 
 irqreturn_t ivtv_irq_handler(int irq, void *dev_id);
 
-void ivtv_irq_work_handler(struct work_struct *work);
+void ivtv_irq_work_handler(struct kthread_work *work);
 void ivtv_dma_stream_dec_prepare(struct ivtv_stream *s, u32 offset, int lock);
 void ivtv_unfinished_dma(unsigned long arg);
 
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index f4a7840bf42c..42c7fafc8bfe 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -37,9 +37,9 @@ void __cachefiles_printk_object(struct cachefiles_object *object,
 
         printk(KERN_ERR "%sobject: OBJ%x\n",
                prefix, object->fscache.debug_id);
-        printk(KERN_ERR "%sobjstate=%s fl=%lx swfl=%lx ev=%lx[%lx]\n",
+        printk(KERN_ERR "%sobjstate=%s fl=%lx wbusy=%x ev=%lx[%lx]\n",
                prefix, fscache_object_states[object->fscache.state],
-               object->fscache.flags, object->fscache.work.flags,
+               object->fscache.flags, work_busy(&object->fscache.work),
                object->fscache.events,
                object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK);
         printk(KERN_ERR "%sops=%u inp=%u exc=%u\n",
@@ -212,7 +212,7 @@ wait_for_old_object:
 
                 /* if the object we're waiting for is queued for processing,
                  * then just put ourselves on the queue behind it */
-                if (slow_work_is_queued(&xobject->fscache.work)) {
+                if (work_pending(&xobject->fscache.work)) {
                         _debug("queue OBJ%x behind OBJ%x immediately",
                                object->fscache.debug_id,
                                xobject->fscache.debug_id);
@@ -220,8 +220,7 @@ wait_for_old_object:
                 }
 
                 /* otherwise we sleep until either the object we're waiting for
-                 * is done, or the slow-work facility wants the thread back to
-                 * do other work */
+                 * is done, or the fscache_object is congested */
                 wq = bit_waitqueue(&xobject->flags, CACHEFILES_OBJECT_ACTIVE);
                 init_wait(&wait);
                 requeue = false;
@@ -229,8 +228,8 @@ wait_for_old_object:
                         prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
                         if (!test_bit(CACHEFILES_OBJECT_ACTIVE, &xobject->flags))
                                 break;
-                        requeue = slow_work_sleep_till_thread_needed(
-                                &object->fscache.work, &timeout);
+
+                        requeue = fscache_object_sleep_till_congested(&timeout);
                 } while (timeout > 0 && !requeue);
                 finish_wait(wq, &wait);
 
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 0f0d41fbb03f..0e3c0924cc3a 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -422,7 +422,7 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
         shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
 
         op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
-        op->op.flags |= FSCACHE_OP_FAST;
+        op->op.flags |= FSCACHE_OP_ASYNC;
         op->op.processor = cachefiles_read_copier;
 
         pagevec_init(&pagevec, 0);
@@ -729,7 +729,7 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
         pagevec_init(&pagevec, 0);
 
         op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
-        op->op.flags |= FSCACHE_OP_FAST;
+        op->op.flags |= FSCACHE_OP_ASYNC;
         op->op.processor = cachefiles_read_copier;
 
         INIT_LIST_HEAD(&backpages);
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index 5739fd7f88b4..efcb3a78a327 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -2,7 +2,6 @@ config CIFS
         tristate "CIFS support (advanced network filesystem, SMBFS successor)"
         depends on INET
         select NLS
-        select SLOW_WORK
         help
           This is the client VFS module for the Common Internet File System
           (CIFS) protocol which is the successor to the Server Message Block
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 8a2cf129e535..5ac541a30c1d 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -939,15 +939,10 @@ init_cifs(void)
         if (rc)
                 goto out_unregister_key_type;
 #endif
-        rc = slow_work_register_user(THIS_MODULE);
-        if (rc)
-                goto out_unregister_resolver_key;
 
         return 0;
 
- out_unregister_resolver_key:
 #ifdef CONFIG_CIFS_DFS_UPCALL
-        cifs_exit_dns_resolver();
  out_unregister_key_type:
 #endif
 #ifdef CONFIG_CIFS_UPCALL
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 59906146ad36..0cdfb8c32ac6 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -22,7 +22,7 @@
 #include <linux/in.h>
 #include <linux/in6.h>
 #include <linux/slab.h>
-#include <linux/slow-work.h>
+#include <linux/workqueue.h>
 #include "cifs_fs_sb.h"
 #include "cifsacl.h"
 /*
@@ -356,7 +356,7 @@ struct cifsFileInfo {
         atomic_t count;         /* reference count */
         struct mutex fh_mutex; /* prevents reopen race after dead ses*/
         struct cifs_search_info srch_inf;
-        struct slow_work oplock_break; /* slow_work job for oplock breaks */
+        struct work_struct oplock_break; /* work for oplock breaks */
 };
 
 /* Take a reference on the file private data */
@@ -728,6 +728,10 @@ GLOBAL_EXTERN unsigned int cifs_min_rcv;    /* min size of big ntwrk buf pool */
 GLOBAL_EXTERN unsigned int cifs_min_small;  /* min size of small buf pool */
 GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/
 
+void cifs_oplock_break(struct work_struct *work);
+void cifs_oplock_break_get(struct cifsFileInfo *cfile);
+void cifs_oplock_break_put(struct cifsFileInfo *cfile);
+
 extern const struct slow_work_ops cifs_oplock_break_ops;
 
 #endif  /* _CIFS_GLOB_H */
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index a7de5e9fff11..578d88c5b46e 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -157,7 +157,7 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle,
         mutex_init(&pCifsFile->lock_mutex);
         INIT_LIST_HEAD(&pCifsFile->llist);
         atomic_set(&pCifsFile->count, 1);
-        slow_work_init(&pCifsFile->oplock_break, &cifs_oplock_break_ops);
+        INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
 
         write_lock(&GlobalSMBSeslock);
         list_add(&pCifsFile->tlist, &cifs_sb->tcon->openFileList);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index fa04a00d126d..db11fdef0e92 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2307,8 +2307,7 @@ static void cifs_invalidate_page(struct page *page, unsigned long offset)
                 cifs_fscache_invalidate_page(page, &cifsi->vfs_inode);
 }
 
-static void
-cifs_oplock_break(struct slow_work *work)
+void cifs_oplock_break(struct work_struct *work)
 {
         struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
                                                   oplock_break);
@@ -2345,33 +2344,30 @@ cifs_oplock_break(struct slow_work *work)
                                  LOCKING_ANDX_OPLOCK_RELEASE, false);
                 cFYI(1, "Oplock release rc = %d", rc);
         }
+
+        /*
+         * We might have kicked in before is_valid_oplock_break()
+         * finished grabbing reference for us.  Make sure it's done by
+         * waiting for GlobalSMSSeslock.
+         */
+        write_lock(&GlobalSMBSeslock);
+        write_unlock(&GlobalSMBSeslock);
+
+        cifs_oplock_break_put(cfile);
 }
 
-static int
-cifs_oplock_break_get(struct slow_work *work)
+void cifs_oplock_break_get(struct cifsFileInfo *cfile)
 {
-        struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
-                                                  oplock_break);
         mntget(cfile->mnt);
         cifsFileInfo_get(cfile);
-        return 0;
 }
 
-static void
-cifs_oplock_break_put(struct slow_work *work)
+void cifs_oplock_break_put(struct cifsFileInfo *cfile)
 {
-        struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
-                                                  oplock_break);
         mntput(cfile->mnt);
         cifsFileInfo_put(cfile);
 }
 
-const struct slow_work_ops cifs_oplock_break_ops = {
-        .get_ref        = cifs_oplock_break_get,
-        .put_ref        = cifs_oplock_break_put,
-        .execute        = cifs_oplock_break,
-};
-
 const struct address_space_operations cifs_addr_ops = {
         .readpage = cifs_readpage,
         .readpages = cifs_readpages,
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 1394aa37f26c..3ccadc1326d6 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -498,7 +498,6 @@ is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv)
         struct cifsTconInfo *tcon;
         struct cifsInodeInfo *pCifsInode;
         struct cifsFileInfo *netfile;
-        int rc;
 
         cFYI(1, "Checking for oplock break or dnotify response");
         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
@@ -583,13 +582,18 @@ is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv)
                                 pCifsInode->clientCanCacheAll = false;
                                 if (pSMB->OplockLevel == 0)
                                         pCifsInode->clientCanCacheRead = false;
-                                rc = slow_work_enqueue(&netfile->oplock_break);
-                                if (rc) {
-                                        cERROR(1, "failed to enqueue oplock "
-                                                   "break: %d\n", rc);
-                                } else {
-                                        netfile->oplock_break_cancelled = false;
-                                }
+
+                                /*
+                                 * cifs_oplock_break_put() can't be called
+                                 * from here.  Get reference after queueing
+                                 * succeeded.  cifs_oplock_break() will
+                                 * synchronize using GlobalSMSSeslock.
+                                 */
+                                if (queue_work(system_nrt_wq,
+                                               &netfile->oplock_break))
+                                        cifs_oplock_break_get(netfile);
+                                netfile->oplock_break_cancelled = false;
+
                                 read_unlock(&GlobalSMBSeslock);
                                 read_unlock(&cifs_tcp_ses_lock);
                                 return true;
diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig
index cc94bb9563f2..3f6dfa989881 100644
--- a/fs/fscache/Kconfig
+++ b/fs/fscache/Kconfig
@@ -1,7 +1,6 @@
 
 config FSCACHE
         tristate "General filesystem local caching manager"
-        select SLOW_WORK
         help
           This option enables a generic filesystem caching manager that can be
           used by various network and other filesystems to cache data locally.
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index edd7434ab6e5..6a026441c5a6 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -82,6 +82,14 @@ extern unsigned fscache_defer_lookup;
 extern unsigned fscache_defer_create;
 extern unsigned fscache_debug;
 extern struct kobject *fscache_root;
+extern struct workqueue_struct *fscache_object_wq;
+extern struct workqueue_struct *fscache_op_wq;
+DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
+
+static inline bool fscache_object_congested(void)
+{
+        return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
+}
 
 extern int fscache_wait_bit(void *);
 extern int fscache_wait_bit_interruptible(void *);
diff --git a/fs/fscache/main.c b/fs/fscache/main.c
index add6bdb53f04..f9d856773f79 100644
--- a/fs/fscache/main.c
+++ b/fs/fscache/main.c
@@ -15,6 +15,7 @@
 #include <linux/sched.h>
 #include <linux/completion.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 #include "internal.h"
 
 MODULE_DESCRIPTION("FS Cache Manager");
@@ -40,22 +41,105 @@ MODULE_PARM_DESC(fscache_debug,
                  "FS-Cache debugging mask");
 
 struct kobject *fscache_root;
+struct workqueue_struct *fscache_object_wq;
+struct workqueue_struct *fscache_op_wq;
+
+DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
+
+/* these values serve as lower bounds, will be adjusted in fscache_init() */
+static unsigned fscache_object_max_active = 4;
+static unsigned fscache_op_max_active = 2;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table_header *fscache_sysctl_header;
+
+static int fscache_max_active_sysctl(struct ctl_table *table, int write,
+                                     void __user *buffer,
+                                     size_t *lenp, loff_t *ppos)
+{
+        struct workqueue_struct **wqp = table->extra1;
+        unsigned int *datap = table->data;
+        int ret;
+
+        ret = proc_dointvec(table, write, buffer, lenp, ppos);
+        if (ret == 0)
+                workqueue_set_max_active(*wqp, *datap);
+        return ret;
+}
+
+ctl_table fscache_sysctls[] = {
+        {
+                .procname       = "object_max_active",
+                .data           = &fscache_object_max_active,
+                .maxlen         = sizeof(unsigned),
+                .mode           = 0644,
+                .proc_handler   = fscache_max_active_sysctl,
+                .extra1         = &fscache_object_wq,
+        },
+        {
+                .procname       = "operation_max_active",
+                .data           = &fscache_op_max_active,
+                .maxlen         = sizeof(unsigned),
+                .mode           = 0644,
+                .proc_handler   = fscache_max_active_sysctl,
+                .extra1         = &fscache_op_wq,
+        },
+        {}
+};
+
+ctl_table fscache_sysctls_root[] = {
+        {
+                .procname       = "fscache",
+                .mode           = 0555,
+                .child          = fscache_sysctls,
+        },
+        {}
+};
+#endif
 
 /*
  * initialise the fs caching module
  */
 static int __init fscache_init(void)
 {
+        unsigned int nr_cpus = num_possible_cpus();
+        unsigned int cpu;
         int ret;
 
-        ret = slow_work_register_user(THIS_MODULE);
-        if (ret < 0)
-                goto error_slow_work;
+        fscache_object_max_active =
+                clamp_val(nr_cpus,
+                          fscache_object_max_active, WQ_UNBOUND_MAX_ACTIVE);
+
+        ret = -ENOMEM;
+        fscache_object_wq = alloc_workqueue("fscache_object", WQ_UNBOUND,
+                                            fscache_object_max_active);
+        if (!fscache_object_wq)
+                goto error_object_wq;
+
+        fscache_op_max_active =
+                clamp_val(fscache_object_max_active / 2,
+                          fscache_op_max_active, WQ_UNBOUND_MAX_ACTIVE);
+
+        ret = -ENOMEM;
+        fscache_op_wq = alloc_workqueue("fscache_operation", WQ_UNBOUND,
+                                        fscache_op_max_active);
+        if (!fscache_op_wq)
+                goto error_op_wq;
+
+        for_each_possible_cpu(cpu)
+                init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
 
         ret = fscache_proc_init();
         if (ret < 0)
                 goto error_proc;
 
+#ifdef CONFIG_SYSCTL
+        ret = -ENOMEM;
+        fscache_sysctl_header = register_sysctl_table(fscache_sysctls_root);
+        if (!fscache_sysctl_header)
+                goto error_sysctl;
+#endif
+
         fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
                                                sizeof(struct fscache_cookie),
                                                0,
@@ -78,10 +162,16 @@ static int __init fscache_init(void)
 error_kobj:
         kmem_cache_destroy(fscache_cookie_jar);
 error_cookie_jar:
+#ifdef CONFIG_SYSCTL
+        unregister_sysctl_table(fscache_sysctl_header);
+error_sysctl:
+#endif
         fscache_proc_cleanup();
 error_proc:
-        slow_work_unregister_user(THIS_MODULE);
-error_slow_work:
+        destroy_workqueue(fscache_op_wq);
+error_op_wq:
+        destroy_workqueue(fscache_object_wq);
+error_object_wq:
         return ret;
 }
 
@@ -96,8 +186,12 @@ static void __exit fscache_exit(void)
 
         kobject_put(fscache_root);
         kmem_cache_destroy(fscache_cookie_jar);
+#ifdef CONFIG_SYSCTL
+        unregister_sysctl_table(fscache_sysctl_header);
+#endif
         fscache_proc_cleanup();
-        slow_work_unregister_user(THIS_MODULE);
+        destroy_workqueue(fscache_op_wq);
+        destroy_workqueue(fscache_object_wq);
         printk(KERN_NOTICE "FS-Cache: Unloaded\n");
 }
 
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
index 4a8eb31c5338..ebe29c581380 100644
--- a/fs/fscache/object-list.c
+++ b/fs/fscache/object-list.c
@@ -34,8 +34,8 @@ struct fscache_objlist_data {
 #define FSCACHE_OBJLIST_CONFIG_NOREADS  0x00000200      /* show objects without active reads */
 #define FSCACHE_OBJLIST_CONFIG_EVENTS   0x00000400      /* show objects with events */
 #define FSCACHE_OBJLIST_CONFIG_NOEVENTS 0x00000800      /* show objects without no events */
-#define FSCACHE_OBJLIST_CONFIG_WORK     0x00001000      /* show objects with slow work */
-#define FSCACHE_OBJLIST_CONFIG_NOWORK   0x00002000      /* show objects without slow work */
+#define FSCACHE_OBJLIST_CONFIG_WORK     0x00001000      /* show objects with work */
+#define FSCACHE_OBJLIST_CONFIG_NOWORK   0x00002000      /* show objects without work */
 
         u8              buf[512];       /* key and aux data buffer */
 };
@@ -231,12 +231,11 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
                        READS, NOREADS);
                 FILTER(obj->events & obj->event_mask,
                        EVENTS, NOEVENTS);
-                FILTER(obj->work.flags & ~(1UL << SLOW_WORK_VERY_SLOW),
-                       WORK, NOWORK);
+                FILTER(work_busy(&obj->work), WORK, NOWORK);
         }
 
         seq_printf(m,
-                   "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1lx | ",
+                   "%8x %8x %s %5u %3u %3u %3u %2u %5u %2lx %2lx %1lx %1x | ",
                    obj->debug_id,
                    obj->parent ? obj->parent->debug_id : -1,
                    fscache_object_states_short[obj->state],
@@ -249,7 +248,7 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
                    obj->event_mask & FSCACHE_OBJECT_EVENTS_MASK,
                    obj->events,
                    obj->flags,
-                   obj->work.flags);
+                   work_busy(&obj->work));
 
         no_cookie = true;
         keylen = auxlen = 0;
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 0b589a9b4ffc..b6b897c550ac 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -14,7 +14,6 @@
 
 #define FSCACHE_DEBUG_LEVEL COOKIE
 #include <linux/module.h>
-#include <linux/seq_file.h>
 #include "internal.h"
 
 const char *fscache_object_states[FSCACHE_OBJECT__NSTATES] = {
@@ -50,12 +49,8 @@ const char fscache_object_states_short[FSCACHE_OBJECT__NSTATES][5] = {
         [FSCACHE_OBJECT_DEAD]           = "DEAD",
 };
 
-static void fscache_object_slow_work_put_ref(struct slow_work *);
-static int  fscache_object_slow_work_get_ref(struct slow_work *);
-static void fscache_object_slow_work_execute(struct slow_work *);
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_object_slow_work_desc(struct slow_work *, struct seq_file *);
-#endif
+static int  fscache_get_object(struct fscache_object *);
+static void fscache_put_object(struct fscache_object *);
 static void fscache_initialise_object(struct fscache_object *);
 static void fscache_lookup_object(struct fscache_object *);
 static void fscache_object_available(struct fscache_object *);
@@ -64,17 +59,6 @@ static void fscache_withdraw_object(struct fscache_object *);
 static void fscache_enqueue_dependents(struct fscache_object *);
 static void fscache_dequeue_object(struct fscache_object *);
 
-const struct slow_work_ops fscache_object_slow_work_ops = {
-        .owner          = THIS_MODULE,
-        .get_ref        = fscache_object_slow_work_get_ref,
-        .put_ref        = fscache_object_slow_work_put_ref,
-        .execute        = fscache_object_slow_work_execute,
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        .desc           = fscache_object_slow_work_desc,
-#endif
-};
-EXPORT_SYMBOL(fscache_object_slow_work_ops);
-
 /*
  * we need to notify the parent when an op completes that we had outstanding
  * upon it
@@ -345,7 +329,7 @@ unsupported_event:
 /*
  * execute an object
  */
-static void fscache_object_slow_work_execute(struct slow_work *work)
+void fscache_object_work_func(struct work_struct *work)
 {
         struct fscache_object *object =
                 container_of(work, struct fscache_object, work);
@@ -359,23 +343,9 @@ static void fscache_object_slow_work_execute(struct slow_work *work)
         if (object->events & object->event_mask)
                 fscache_enqueue_object(object);
         clear_bit(FSCACHE_OBJECT_EV_REQUEUE, &object->events);
+        fscache_put_object(object);
 }
-
-/*
- * describe an object for slow-work debugging
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_object_slow_work_desc(struct slow_work *work,
-                                          struct seq_file *m)
-{
-        struct fscache_object *object =
-                container_of(work, struct fscache_object, work);
-
-        seq_printf(m, "FSC: OBJ%x: %s",
-                   object->debug_id,
-                   fscache_object_states_short[object->state]);
-}
-#endif
+EXPORT_SYMBOL(fscache_object_work_func);
 
 /*
  * initialise an object
@@ -393,7 +363,6 @@ static void fscache_initialise_object(struct fscache_object *object)
         _enter("");
         ASSERT(object->cookie != NULL);
         ASSERT(object->cookie->parent != NULL);
-        ASSERT(list_empty(&object->work.link));
 
         if (object->events & ((1 << FSCACHE_OBJECT_EV_ERROR) |
                               (1 << FSCACHE_OBJECT_EV_RELEASE) |
@@ -671,10 +640,8 @@ static void fscache_drop_object(struct fscache_object *object)
                 object->parent = NULL;
         }
 
-        /* this just shifts the object release to the slow work processor */
-        fscache_stat(&fscache_n_cop_put_object);
-        object->cache->ops->put_object(object);
-        fscache_stat_d(&fscache_n_cop_put_object);
+        /* this just shifts the object release to the work processor */
+        fscache_put_object(object);
 
         _leave("");
 }
@@ -758,12 +725,10 @@ void fscache_withdrawing_object(struct fscache_cache *cache,
 }
 
 /*
- * allow the slow work item processor to get a ref on an object
+ * get a ref on an object
  */
-static int fscache_object_slow_work_get_ref(struct slow_work *work)
+static int fscache_get_object(struct fscache_object *object)
 {
-        struct fscache_object *object =
-                container_of(work, struct fscache_object, work);
         int ret;
 
         fscache_stat(&fscache_n_cop_grab_object);
@@ -773,13 +738,10 @@ static int fscache_object_slow_work_get_ref(struct slow_work *work)
 }
 
 /*
- * allow the slow work item processor to discard a ref on a work item
+ * discard a ref on a work item
  */
-static void fscache_object_slow_work_put_ref(struct slow_work *work)
+static void fscache_put_object(struct fscache_object *object)
 {
-        struct fscache_object *object =
-                container_of(work, struct fscache_object, work);
-
         fscache_stat(&fscache_n_cop_put_object);
         object->cache->ops->put_object(object);
         fscache_stat_d(&fscache_n_cop_put_object);
@@ -792,8 +754,48 @@ void fscache_enqueue_object(struct fscache_object *object)
 {
         _enter("{OBJ%x}", object->debug_id);
 
-        slow_work_enqueue(&object->work);
+        if (fscache_get_object(object) >= 0) {
+                wait_queue_head_t *cong_wq =
+                        &get_cpu_var(fscache_object_cong_wait);
+
+                if (queue_work(fscache_object_wq, &object->work)) {
+                        if (fscache_object_congested())
+                                wake_up(cong_wq);
+                } else
+                        fscache_put_object(object);
+
+                put_cpu_var(fscache_object_cong_wait);
+        }
+}
+
+/**
+ * fscache_object_sleep_till_congested - Sleep until object wq is congested
+ * @timoutp: Scheduler sleep timeout
+ *
+ * Allow an object handler to sleep until the object workqueue is congested.
+ *
+ * The caller must set up a wake up event before calling this and must have set
+ * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own
+ * condition before calling this function as no test is made here.
+ *
+ * %true is returned if the object wq is congested, %false otherwise.
+ */
+bool fscache_object_sleep_till_congested(signed long *timeoutp)
+{
+        wait_queue_head_t *cong_wq = &__get_cpu_var(fscache_object_cong_wait);
+        DEFINE_WAIT(wait);
+
+        if (fscache_object_congested())
+                return true;
+
+        add_wait_queue_exclusive(cong_wq, &wait);
+        if (!fscache_object_congested())
+                *timeoutp = schedule_timeout(*timeoutp);
+        finish_wait(cong_wq, &wait);
+
+        return fscache_object_congested();
 }
+EXPORT_SYMBOL_GPL(fscache_object_sleep_till_congested);
 
 /*
  * enqueue the dependents of an object for metadata-type processing
@@ -819,9 +821,7 @@ static void fscache_enqueue_dependents(struct fscache_object *object)
 
                 /* sort onto appropriate lists */
                 fscache_enqueue_object(dep);
-                fscache_stat(&fscache_n_cop_put_object);
-                dep->cache->ops->put_object(dep);
-                fscache_stat_d(&fscache_n_cop_put_object);
+                fscache_put_object(dep);
 
                 if (!list_empty(&object->dependents))
                         cond_resched_lock(&object->lock);
diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index f17cecafae44..b9f34eaede09 100644
--- a/fs/fscache/operation.c
+++ b/fs/fscache/operation.c
@@ -42,16 +42,12 @@ void fscache_enqueue_operation(struct fscache_operation *op)
 
         fscache_stat(&fscache_n_op_enqueue);
         switch (op->flags & FSCACHE_OP_TYPE) {
-        case FSCACHE_OP_FAST:
-                _debug("queue fast");
+        case FSCACHE_OP_ASYNC:
+                _debug("queue async");
                 atomic_inc(&op->usage);
-                if (!schedule_work(&op->fast_work))
+                if (!queue_work(fscache_op_wq, &op->work))
                         fscache_put_operation(op);
                 break;
-        case FSCACHE_OP_SLOW:
-                _debug("queue slow");
-                slow_work_enqueue(&op->slow_work);
-                break;
         case FSCACHE_OP_MYTHREAD:
                 _debug("queue for caller's attention");
                 break;
@@ -455,36 +451,13 @@ void fscache_operation_gc(struct work_struct *work)
 }
 
 /*
- * allow the slow work item processor to get a ref on an operation
- */
-static int fscache_op_get_ref(struct slow_work *work)
-{
-        struct fscache_operation *op =
-                container_of(work, struct fscache_operation, slow_work);
-
-        atomic_inc(&op->usage);
-        return 0;
-}
-
-/*
- * allow the slow work item processor to discard a ref on an operation
- */
-static void fscache_op_put_ref(struct slow_work *work)
-{
-        struct fscache_operation *op =
-                container_of(work, struct fscache_operation, slow_work);
-
-        fscache_put_operation(op);
-}
-
-/*
- * execute an operation using the slow thread pool to provide processing context
- * - the caller holds a ref to this object, so we don't need to hold one
+ * execute an operation using fs_op_wq to provide processing context -
+ * the caller holds a ref to this object, so we don't need to hold one
  */
-static void fscache_op_execute(struct slow_work *work)
+void fscache_op_work_func(struct work_struct *work)
 {
         struct fscache_operation *op =
-                container_of(work, struct fscache_operation, slow_work);
+                container_of(work, struct fscache_operation, work);
         unsigned long start;
 
         _enter("{OBJ%x OP%x,%d}",
@@ -494,31 +467,7 @@ static void fscache_op_execute(struct slow_work *work)
         start = jiffies;
         op->processor(op);
         fscache_hist(fscache_ops_histogram, start);
+        fscache_put_operation(op);
 
         _leave("");
 }
-
-/*
- * describe an operation for slow-work debugging
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-static void fscache_op_desc(struct slow_work *work, struct seq_file *m)
-{
-        struct fscache_operation *op =
-                container_of(work, struct fscache_operation, slow_work);
-
-        seq_printf(m, "FSC: OBJ%x OP%x: %s/%s fl=%lx",
-                   op->object->debug_id, op->debug_id,
-                   op->name, op->state, op->flags);
-}
-#endif
-
-const struct slow_work_ops fscache_op_slow_work_ops = {
-        .owner          = THIS_MODULE,
-        .get_ref        = fscache_op_get_ref,
-        .put_ref        = fscache_op_put_ref,
-        .execute        = fscache_op_execute,
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        .desc           = fscache_op_desc,
-#endif
-};
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 723b889fd219..41c441c2058d 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -105,7 +105,7 @@ bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
 
 page_busy:
         /* we might want to wait here, but that could deadlock the allocator as
-         * the slow-work threads writing to the cache may all end up sleeping
+         * the work threads writing to the cache may all end up sleeping
          * on memory allocation */
         fscache_stat(&fscache_n_store_vmscan_busy);
         return false;
@@ -188,9 +188,8 @@ int __fscache_attr_changed(struct fscache_cookie *cookie)
                 return -ENOMEM;
         }
 
-        fscache_operation_init(op, NULL);
-        fscache_operation_init_slow(op, fscache_attr_changed_op);
-        op->flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_EXCLUSIVE);
+        fscache_operation_init(op, fscache_attr_changed_op, NULL);
+        op->flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_EXCLUSIVE);
         fscache_set_op_name(op, "Attr");
 
         spin_lock(&cookie->lock);
@@ -218,24 +217,6 @@ nobufs:
 EXPORT_SYMBOL(__fscache_attr_changed);
 
 /*
- * handle secondary execution given to a retrieval op on behalf of the
- * cache
- */
-static void fscache_retrieval_work(struct work_struct *work)
-{
-        struct fscache_retrieval *op =
-                container_of(work, struct fscache_retrieval, op.fast_work);
-        unsigned long start;
-
-        _enter("{OP%x}", op->op.debug_id);
-
-        start = jiffies;
-        op->op.processor(&op->op);
-        fscache_hist(fscache_ops_histogram, start);
-        fscache_put_operation(&op->op);
-}
-
-/*
  * release a retrieval op reference
  */
 static void fscache_release_retrieval_op(struct fscache_operation *_op)
@@ -269,13 +250,12 @@ static struct fscache_retrieval *fscache_alloc_retrieval(
                 return NULL;
         }
 
-        fscache_operation_init(&op->op, fscache_release_retrieval_op);
+        fscache_operation_init(&op->op, NULL, fscache_release_retrieval_op);
         op->op.flags    = FSCACHE_OP_MYTHREAD | (1 << FSCACHE_OP_WAITING);
         op->mapping     = mapping;
         op->end_io_func = end_io_func;
         op->context     = context;
         op->start_time  = jiffies;
-        INIT_WORK(&op->op.fast_work, fscache_retrieval_work);
         INIT_LIST_HEAD(&op->to_do);
         fscache_set_op_name(&op->op, "Retr");
         return op;
@@ -795,9 +775,9 @@ int __fscache_write_page(struct fscache_cookie *cookie,
         if (!op)
                 goto nomem;
 
-        fscache_operation_init(&op->op, fscache_release_write_op);
-        fscache_operation_init_slow(&op->op, fscache_write_op);
-        op->op.flags = FSCACHE_OP_SLOW | (1 << FSCACHE_OP_WAITING);
+        fscache_operation_init(&op->op, fscache_write_op,
+                               fscache_release_write_op);
+        op->op.flags = FSCACHE_OP_ASYNC | (1 << FSCACHE_OP_WAITING);
         fscache_set_op_name(&op->op, "Write1");
 
         ret = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
@@ -852,7 +832,7 @@ int __fscache_write_page(struct fscache_cookie *cookie,
         fscache_stat(&fscache_n_store_ops);
         fscache_stat(&fscache_n_stores_ok);
 
-        /* the slow work queue now carries its own ref on the object */
+        /* the work queue now carries its own ref on the object */
         fscache_put_operation(&op->op);
         _leave(" = 0");
         return 0;
diff --git a/fs/gfs2/Kconfig b/fs/gfs2/Kconfig
index a47b43107112..cc9665522148 100644
--- a/fs/gfs2/Kconfig
+++ b/fs/gfs2/Kconfig
@@ -7,7 +7,6 @@ config GFS2_FS
         select IP_SCTP if DLM_SCTP
         select FS_POSIX_ACL
         select CRC32
-        select SLOW_WORK
         select QUOTACTL
         help
           A cluster filesystem.
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 8fcbce48a128..fdbf4b366fa5 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -12,7 +12,6 @@
 
 #include <linux/fs.h>
 #include <linux/workqueue.h>
-#include <linux/slow-work.h>
 #include <linux/dlm.h>
 #include <linux/buffer_head.h>
 
@@ -383,7 +382,7 @@ struct gfs2_journal_extent {
 struct gfs2_jdesc {
         struct list_head jd_list;
         struct list_head extent_list;
-        struct slow_work jd_work;
+        struct work_struct jd_work;
         struct inode *jd_inode;
         unsigned long jd_flags;
 #define JDF_RECOVERY 1
diff --git a/fs/gfs2/main.c b/fs/gfs2/main.c
index fb2a5f93b7c3..b1e9630eb46a 100644
--- a/fs/gfs2/main.c
+++ b/fs/gfs2/main.c
@@ -15,7 +15,6 @@
 #include <linux/init.h>
 #include <linux/gfs2_ondisk.h>
 #include <asm/atomic.h>
-#include <linux/slow-work.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -24,6 +23,7 @@
 #include "util.h"
 #include "glock.h"
 #include "quota.h"
+#include "recovery.h"
 
 static struct shrinker qd_shrinker = {
         .shrink = gfs2_shrink_qd_memory,
@@ -138,9 +138,11 @@ static int __init init_gfs2_fs(void)
         if (error)
                 goto fail_unregister;
 
-        error = slow_work_register_user(THIS_MODULE);
-        if (error)
-                goto fail_slow;
+        error = -ENOMEM;
+        gfs_recovery_wq = alloc_workqueue("gfs_recovery",
+                                          WQ_NON_REENTRANT | WQ_RESCUER, 0);
+        if (!gfs_recovery_wq)
+                goto fail_wq;
 
         gfs2_register_debugfs();
 
@@ -148,7 +150,7 @@ static int __init init_gfs2_fs(void)
 
         return 0;
 
-fail_slow:
+fail_wq:
         unregister_filesystem(&gfs2meta_fs_type);
 fail_unregister:
         unregister_filesystem(&gfs2_fs_type);
@@ -190,7 +192,7 @@ static void __exit exit_gfs2_fs(void)
         gfs2_unregister_debugfs();
         unregister_filesystem(&gfs2_fs_type);
         unregister_filesystem(&gfs2meta_fs_type);
-        slow_work_unregister_user(THIS_MODULE);
+        destroy_workqueue(gfs_recovery_wq);
 
         kmem_cache_destroy(gfs2_quotad_cachep);
         kmem_cache_destroy(gfs2_rgrpd_cachep);
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 45a4a36195d8..4f44bdeb2f03 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -17,7 +17,6 @@
 #include <linux/namei.h>
 #include <linux/mount.h>
 #include <linux/gfs2_ondisk.h>
-#include <linux/slow-work.h>
 #include <linux/quotaops.h>
 
 #include "gfs2.h"
@@ -673,7 +672,7 @@ static int gfs2_jindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ji_gh)
                         break;
 
                 INIT_LIST_HEAD(&jd->extent_list);
-                slow_work_init(&jd->jd_work, &gfs2_recover_ops);
+                INIT_WORK(&jd->jd_work, gfs2_recover_func);
                 jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1);
                 if (!jd->jd_inode || IS_ERR(jd->jd_inode)) {
                         if (!jd->jd_inode)
@@ -782,7 +781,8 @@ static int init_journal(struct gfs2_sbd *sdp, int undo)
         if (sdp->sd_lockstruct.ls_first) {
                 unsigned int x;
                 for (x = 0; x < sdp->sd_journals; x++) {
-                        error = gfs2_recover_journal(gfs2_jdesc_find(sdp, x));
+                        error = gfs2_recover_journal(gfs2_jdesc_find(sdp, x),
+                                                     true);
                         if (error) {
                                 fs_err(sdp, "error recovering journal %u: %d\n",
                                        x, error);
@@ -792,7 +792,7 @@ static int init_journal(struct gfs2_sbd *sdp, int undo)
 
                 gfs2_others_may_mount(sdp);
         } else if (!sdp->sd_args.ar_spectator) {
-                error = gfs2_recover_journal(sdp->sd_jdesc);
+                error = gfs2_recover_journal(sdp->sd_jdesc, true);
                 if (error) {
                         fs_err(sdp, "error recovering my journal: %d\n", error);
                         goto fail_jinode_gh;
diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index 4b9bece3d437..f7f89a94a5a4 100644
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -14,7 +14,6 @@
 #include <linux/buffer_head.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/crc32.h>
-#include <linux/slow-work.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -28,6 +27,8 @@
 #include "util.h"
 #include "dir.h"
 
+struct workqueue_struct *gfs_recovery_wq;
+
 int gfs2_replay_read_block(struct gfs2_jdesc *jd, unsigned int blk,
                            struct buffer_head **bh)
 {
@@ -443,23 +444,7 @@ static void gfs2_recovery_done(struct gfs2_sbd *sdp, unsigned int jid,
         kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);
 }
 
-static int gfs2_recover_get_ref(struct slow_work *work)
-{
-        struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
-        if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
-                return -EBUSY;
-        return 0;
-}
-
-static void gfs2_recover_put_ref(struct slow_work *work)
-{
-        struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
-        clear_bit(JDF_RECOVERY, &jd->jd_flags);
-        smp_mb__after_clear_bit();
-        wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
-}
-
-static void gfs2_recover_work(struct slow_work *work)
+void gfs2_recover_func(struct work_struct *work)
 {
         struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
         struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
@@ -578,7 +563,7 @@ static void gfs2_recover_work(struct slow_work *work)
                 gfs2_glock_dq_uninit(&j_gh);
 
         fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
-        return;
+        goto done;
 
 fail_gunlock_tr:
         gfs2_glock_dq_uninit(&t_gh);
@@ -590,32 +575,35 @@ fail_gunlock_j:
         }
 
         fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
-
 fail:
         gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
+done:
+        clear_bit(JDF_RECOVERY, &jd->jd_flags);
+        smp_mb__after_clear_bit();
+        wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
 }
 
-struct slow_work_ops gfs2_recover_ops = {
-        .owner   = THIS_MODULE,
-        .get_ref = gfs2_recover_get_ref,
-        .put_ref = gfs2_recover_put_ref,
-        .execute = gfs2_recover_work,
-};
-
-
 static int gfs2_recovery_wait(void *word)
 {
         schedule();
         return 0;
 }
 
-int gfs2_recover_journal(struct gfs2_jdesc *jd)
+int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
 {
         int rv;
-        rv = slow_work_enqueue(&jd->jd_work);
-        if (rv)
-                return rv;
-        wait_on_bit(&jd->jd_flags, JDF_RECOVERY, gfs2_recovery_wait, TASK_UNINTERRUPTIBLE);
+
+        if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
+                return -EBUSY;
+
+        /* we have JDF_RECOVERY, queue should always succeed */
+        rv = queue_work(gfs_recovery_wq, &jd->jd_work);
+        BUG_ON(!rv);
+
+        if (wait)
+                wait_on_bit(&jd->jd_flags, JDF_RECOVERY, gfs2_recovery_wait,
+                            TASK_UNINTERRUPTIBLE);
+
         return 0;
 }
 
diff --git a/fs/gfs2/recovery.h b/fs/gfs2/recovery.h
index 1616ac22569a..2226136c7647 100644
--- a/fs/gfs2/recovery.h
+++ b/fs/gfs2/recovery.h
@@ -12,6 +12,8 @@
 
 #include "incore.h"
 
+extern struct workqueue_struct *gfs_recovery_wq;
+
 static inline void gfs2_replay_incr_blk(struct gfs2_sbd *sdp, unsigned int *blk)
 {
         if (++*blk == sdp->sd_jdesc->jd_blocks)
@@ -27,8 +29,8 @@ extern void gfs2_revoke_clean(struct gfs2_sbd *sdp);
 
 extern int gfs2_find_jhead(struct gfs2_jdesc *jd,
                     struct gfs2_log_header_host *head);
-extern int gfs2_recover_journal(struct gfs2_jdesc *gfs2_jd);
-extern struct slow_work_ops gfs2_recover_ops;
+extern int gfs2_recover_journal(struct gfs2_jdesc *gfs2_jd, bool wait);
+extern void gfs2_recover_func(struct work_struct *work);
 
 #endif /* __RECOVERY_DOT_H__ */
 
diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
index d019d0d55e00..ccacffd2faaa 100644
--- a/fs/gfs2/sys.c
+++ b/fs/gfs2/sys.c
@@ -25,6 +25,7 @@
 #include "quota.h"
 #include "util.h"
 #include "glops.h"
+#include "recovery.h"
 
 struct gfs2_attr {
         struct attribute attr;
@@ -376,7 +377,7 @@ static ssize_t recover_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
         list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
                 if (jd->jd_jid != jid)
                         continue;
-                rv = slow_work_enqueue(&jd->jd_work);
+                rv = gfs2_recover_journal(jd, false);
                 break;
         }
 out:
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 93a1a31b9c2d..c707270bff5a 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -31,7 +31,6 @@
 #include <linux/idr.h>
 
 #include <linux/fb.h>
-#include <linux/slow-work.h>
 
 struct drm_device;
 struct drm_mode_set;
@@ -595,7 +594,7 @@ struct drm_mode_config {
 
         /* output poll support */
         bool poll_enabled;
-        struct delayed_slow_work output_poll_slow_work;
+        struct delayed_work output_poll_work;
 
         /* pointers to standard properties */
         struct list_head property_blob_list;
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index de6b1722cdca..4823af64e9db 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -71,6 +71,8 @@ enum {
         /* migration should happen before other stuff but after perf */
         CPU_PRI_PERF            = 20,
         CPU_PRI_MIGRATION       = 10,
+        /* prepare workqueues for other notifiers */
+        CPU_PRI_WORKQUEUE       = 5,
 };
 
 #ifdef CONFIG_SMP
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index c57db27ac861..b8581c09d19f 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -20,7 +20,7 @@
 
 #include <linux/fscache.h>
 #include <linux/sched.h>
-#include <linux/slow-work.h>
+#include <linux/workqueue.h>
 
 #define NR_MAXCACHES BITS_PER_LONG
 
@@ -76,18 +76,14 @@ typedef void (*fscache_operation_release_t)(struct fscache_operation *op);
 typedef void (*fscache_operation_processor_t)(struct fscache_operation *op);
 
 struct fscache_operation {
-        union {
-                struct work_struct fast_work;   /* record for fast ops */
-                struct slow_work slow_work;     /* record for (very) slow ops */
-        };
+        struct work_struct      work;           /* record for async ops */
         struct list_head        pend_link;      /* link in object->pending_ops */
         struct fscache_object   *object;        /* object to be operated upon */
 
         unsigned long           flags;
 #define FSCACHE_OP_TYPE         0x000f  /* operation type */
-#define FSCACHE_OP_FAST         0x0001  /* - fast op, processor may not sleep for disk */
-#define FSCACHE_OP_SLOW         0x0002  /* - (very) slow op, processor may sleep for disk */
-#define FSCACHE_OP_MYTHREAD     0x0003  /* - processing is done be issuing thread, not pool */
+#define FSCACHE_OP_ASYNC        0x0001  /* - async op, processor may sleep for disk */
+#define FSCACHE_OP_MYTHREAD     0x0002  /* - processing is done be issuing thread, not pool */
 #define FSCACHE_OP_WAITING      4       /* cleared when op is woken */
 #define FSCACHE_OP_EXCLUSIVE    5       /* exclusive op, other ops must wait */
 #define FSCACHE_OP_DEAD         6       /* op is now dead */
@@ -105,7 +101,8 @@ struct fscache_operation {
         /* operation releaser */
         fscache_operation_release_t release;
 
-#ifdef CONFIG_SLOW_WORK_DEBUG
+#ifdef CONFIG_WORKQUEUE_DEBUGFS
+        struct work_struct put_work;    /* work to delay operation put */
         const char *name;               /* operation name */
         const char *state;              /* operation state */
 #define fscache_set_op_name(OP, N)      do { (OP)->name  = (N); } while(0)
@@ -117,7 +114,7 @@ struct fscache_operation {
 };
 
 extern atomic_t fscache_op_debug_id;
-extern const struct slow_work_ops fscache_op_slow_work_ops;
+extern void fscache_op_work_func(struct work_struct *work);
 
 extern void fscache_enqueue_operation(struct fscache_operation *);
 extern void fscache_put_operation(struct fscache_operation *);
@@ -128,33 +125,21 @@ extern void fscache_put_operation(struct fscache_operation *);
  * @release: The release function to assign
  *
  * Do basic initialisation of an operation.  The caller must still set flags,
- * object, either fast_work or slow_work if necessary, and processor if needed.
+ * object and processor if needed.
  */
 static inline void fscache_operation_init(struct fscache_operation *op,
-                                          fscache_operation_release_t release)
+                                        fscache_operation_processor_t processor,
+                                        fscache_operation_release_t release)
 {
+        INIT_WORK(&op->work, fscache_op_work_func);
         atomic_set(&op->usage, 1);
         op->debug_id = atomic_inc_return(&fscache_op_debug_id);
+        op->processor = processor;
         op->release = release;
         INIT_LIST_HEAD(&op->pend_link);
         fscache_set_op_state(op, "Init");
 }
 
-/**
- * fscache_operation_init_slow - Do additional initialisation of a slow op
- * @op: The operation to initialise
- * @processor: The processor function to assign
- *
- * Do additional initialisation of an operation as required for slow work.
- */
-static inline
-void fscache_operation_init_slow(struct fscache_operation *op,
-                                 fscache_operation_processor_t processor)
-{
-        op->processor = processor;
-        slow_work_init(&op->slow_work, &fscache_op_slow_work_ops);
-}
-
 /*
  * data read operation
  */
@@ -389,7 +374,7 @@ struct fscache_object {
         struct fscache_cache    *cache;         /* cache that supplied this object */
         struct fscache_cookie   *cookie;        /* netfs's file/index object */
         struct fscache_object   *parent;        /* parent object */
-        struct slow_work        work;           /* attention scheduling record */
+        struct work_struct      work;           /* attention scheduling record */
         struct list_head        dependents;     /* FIFO of dependent objects */
         struct list_head        dep_link;       /* link in parent's dependents list */
         struct list_head        pending_ops;    /* unstarted operations on this object */
@@ -411,7 +396,7 @@ extern const char *fscache_object_states[];
         (test_bit(FSCACHE_IOERROR, &(obj)->cache->flags) &&     \
          (obj)->state >= FSCACHE_OBJECT_DYING)
 
-extern const struct slow_work_ops fscache_object_slow_work_ops;
+extern void fscache_object_work_func(struct work_struct *work);
 
 /**
  * fscache_object_init - Initialise a cache object description
@@ -433,7 +418,7 @@ void fscache_object_init(struct fscache_object *object,
         spin_lock_init(&object->lock);
         INIT_LIST_HEAD(&object->cache_link);
         INIT_HLIST_NODE(&object->cookie_link);
-        vslow_work_init(&object->work, &fscache_object_slow_work_ops);
+        INIT_WORK(&object->work, fscache_object_work_func);
         INIT_LIST_HEAD(&object->dependents);
         INIT_LIST_HEAD(&object->dep_link);
         INIT_LIST_HEAD(&object->pending_ops);
@@ -534,6 +519,8 @@ extern void fscache_io_error(struct fscache_cache *cache);
 extern void fscache_mark_pages_cached(struct fscache_retrieval *op,
                                       struct pagevec *pagevec);
 
+extern bool fscache_object_sleep_till_congested(signed long *timeoutp);
+
 extern enum fscache_checkaux fscache_check_aux(struct fscache_object *object,
                                                const void *data,
                                                uint16_t datalen);
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index aabc8a13ba71..685ea65eb803 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -30,8 +30,73 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
 void kthread_bind(struct task_struct *k, unsigned int cpu);
 int kthread_stop(struct task_struct *k);
 int kthread_should_stop(void);
+void *kthread_data(struct task_struct *k);
 
 int kthreadd(void *unused);
 extern struct task_struct *kthreadd_task;
 
+/*
+ * Simple work processor based on kthread.
+ *
+ * This provides easier way to make use of kthreads.  A kthread_work
+ * can be queued and flushed using queue/flush_kthread_work()
+ * respectively.  Queued kthread_works are processed by a kthread
+ * running kthread_worker_fn().
+ *
+ * A kthread_work can't be freed while it is executing.
+ */
+struct kthread_work;
+typedef void (*kthread_work_func_t)(struct kthread_work *work);
+
+struct kthread_worker {
+        spinlock_t              lock;
+        struct list_head        work_list;
+        struct task_struct      *task;
+};
+
+struct kthread_work {
+        struct list_head        node;
+        kthread_work_func_t     func;
+        wait_queue_head_t       done;
+        atomic_t                flushing;
+        int                     queue_seq;
+        int                     done_seq;
+};
+
+#define KTHREAD_WORKER_INIT(worker)     {                               \
+        .lock = SPIN_LOCK_UNLOCKED,                                     \
+        .work_list = LIST_HEAD_INIT((worker).work_list),                \
+        }
+
+#define KTHREAD_WORK_INIT(work, fn)     {                               \
+        .node = LIST_HEAD_INIT((work).node),                            \
+        .func = (fn),                                                   \
+        .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),             \
+        .flushing = ATOMIC_INIT(0),                                     \
+        }
+
+#define DEFINE_KTHREAD_WORKER(worker)                                   \
+        struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
+
+#define DEFINE_KTHREAD_WORK(work, fn)                                   \
+        struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
+
+static inline void init_kthread_worker(struct kthread_worker *worker)
+{
+        *worker = (struct kthread_worker)KTHREAD_WORKER_INIT(*worker);
+}
+
+static inline void init_kthread_work(struct kthread_work *work,
+                                     kthread_work_func_t fn)
+{
+        *work = (struct kthread_work)KTHREAD_WORK_INIT(*work, fn);
+}
+
+int kthread_worker_fn(void *worker_ptr);
+
+bool queue_kthread_work(struct kthread_worker *worker,
+                        struct kthread_work *work);
+void flush_kthread_work(struct kthread_work *work);
+void flush_kthread_worker(struct kthread_worker *worker);
+
 #endif /* _LINUX_KTHREAD_H */
diff --git a/include/linux/libata.h b/include/linux/libata.h
index b85f3ff34d7d..f010f18a0f86 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -751,6 +751,7 @@ struct ata_port {
         struct ata_host         *host;
         struct device           *dev;
 
+        struct mutex            scsi_scan_mutex;
         struct delayed_work     hotplug_task;
         struct work_struct      scsi_rescan_task;
 
diff --git a/include/linux/slow-work.h b/include/linux/slow-work.h
deleted file mode 100644
index 13337bf6c3f5..000000000000
--- a/include/linux/slow-work.h
+++ /dev/null
@@ -1,163 +0,0 @@
-/* Worker thread pool for slow items, such as filesystem lookups or mkdirs
- *
- * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- *
- * See Documentation/slow-work.txt
- */
-
-#ifndef _LINUX_SLOW_WORK_H
-#define _LINUX_SLOW_WORK_H
-
-#ifdef CONFIG_SLOW_WORK
-
-#include <linux/sysctl.h>
-#include <linux/timer.h>
-
-struct slow_work;
-#ifdef CONFIG_SLOW_WORK_DEBUG
-struct seq_file;
-#endif
-
-/*
- * The operations used to support slow work items
- */
-struct slow_work_ops {
-        /* owner */
-        struct module *owner;
-
-        /* get a ref on a work item
-         * - return 0 if successful, -ve if not
-         */
-        int (*get_ref)(struct slow_work *work);
-
-        /* discard a ref to a work item */
-        void (*put_ref)(struct slow_work *work);
-
-        /* execute a work item */
-        void (*execute)(struct slow_work *work);
-
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        /* describe a work item for debugfs */
-        void (*desc)(struct slow_work *work, struct seq_file *m);
-#endif
-};
-
-/*
- * A slow work item
- * - A reference is held on the parent object by the thread pool when it is
- *   queued
- */
-struct slow_work {
-        struct module           *owner; /* the owning module */
-        unsigned long           flags;
-#define SLOW_WORK_PENDING       0       /* item pending (further) execution */
-#define SLOW_WORK_EXECUTING     1       /* item currently executing */
-#define SLOW_WORK_ENQ_DEFERRED  2       /* item enqueue deferred */
-#define SLOW_WORK_VERY_SLOW     3       /* item is very slow */
-#define SLOW_WORK_CANCELLING    4       /* item is being cancelled, don't enqueue */
-#define SLOW_WORK_DELAYED       5       /* item is struct delayed_slow_work with active timer */
-        const struct slow_work_ops *ops; /* operations table for this item */
-        struct list_head        link;   /* link in queue */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        struct timespec         mark;   /* jiffies at which queued or exec begun */
-#endif
-};
-
-struct delayed_slow_work {
-        struct slow_work        work;
-        struct timer_list       timer;
-};
-
-/**
- * slow_work_init - Initialise a slow work item
- * @work: The work item to initialise
- * @ops: The operations to use to handle the slow work item
- *
- * Initialise a slow work item.
- */
-static inline void slow_work_init(struct slow_work *work,
-                                  const struct slow_work_ops *ops)
-{
-        work->flags = 0;
-        work->ops = ops;
-        INIT_LIST_HEAD(&work->link);
-}
-
-/**
- * slow_work_init - Initialise a delayed slow work item
- * @work: The work item to initialise
- * @ops: The operations to use to handle the slow work item
- *
- * Initialise a delayed slow work item.
- */
-static inline void delayed_slow_work_init(struct delayed_slow_work *dwork,
-                                          const struct slow_work_ops *ops)
-{
-        init_timer(&dwork->timer);
-        slow_work_init(&dwork->work, ops);
-}
-
-/**
- * vslow_work_init - Initialise a very slow work item
- * @work: The work item to initialise
- * @ops: The operations to use to handle the slow work item
- *
- * Initialise a very slow work item.  This item will be restricted such that
- * only a certain number of the pool threads will be able to execute items of
- * this type.
- */
-static inline void vslow_work_init(struct slow_work *work,
-                                   const struct slow_work_ops *ops)
-{
-        work->flags = 1 << SLOW_WORK_VERY_SLOW;
-        work->ops = ops;
-        INIT_LIST_HEAD(&work->link);
-}
-
-/**
- * slow_work_is_queued - Determine if a slow work item is on the work queue
- * work: The work item to test
- *
- * Determine if the specified slow-work item is on the work queue.  This
- * returns true if it is actually on the queue.
- *
- * If the item is executing and has been marked for requeue when execution
- * finishes, then false will be returned.
- *
- * Anyone wishing to wait for completion of execution can wait on the
- * SLOW_WORK_EXECUTING bit.
- */
-static inline bool slow_work_is_queued(struct slow_work *work)
-{
-        unsigned long flags = work->flags;
-        return flags & SLOW_WORK_PENDING && !(flags & SLOW_WORK_EXECUTING);
-}
-
-extern int slow_work_enqueue(struct slow_work *work);
-extern void slow_work_cancel(struct slow_work *work);
-extern int slow_work_register_user(struct module *owner);
-extern void slow_work_unregister_user(struct module *owner);
-
-extern int delayed_slow_work_enqueue(struct delayed_slow_work *dwork,
-                                     unsigned long delay);
-
-static inline void delayed_slow_work_cancel(struct delayed_slow_work *dwork)
-{
-        slow_work_cancel(&dwork->work);
-}
-
-extern bool slow_work_sleep_till_thread_needed(struct slow_work *work,
-                                               signed long *_timeout);
-
-#ifdef CONFIG_SYSCTL
-extern ctl_table slow_work_sysctls[];
-#endif
-
-#endif /* CONFIG_SLOW_WORK */
-#endif /* _LINUX_SLOW_WORK_H */
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index d0f7c8178498..4f9d277bcd9a 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -9,6 +9,7 @@
 #include <linux/linkage.h>
 #include <linux/bitops.h>
 #include <linux/lockdep.h>
+#include <linux/threads.h>
 #include <asm/atomic.h>
 
 struct workqueue_struct;
@@ -22,12 +23,59 @@ typedef void (*work_func_t)(struct work_struct *work);
  */
 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
 
+enum {
+        WORK_STRUCT_PENDING_BIT = 0,    /* work item is pending execution */
+        WORK_STRUCT_CWQ_BIT     = 1,    /* data points to cwq */
+        WORK_STRUCT_LINKED_BIT  = 2,    /* next work is linked to this one */
+#ifdef CONFIG_DEBUG_OBJECTS_WORK
+        WORK_STRUCT_STATIC_BIT  = 3,    /* static initializer (debugobjects) */
+        WORK_STRUCT_COLOR_SHIFT = 4,    /* color for workqueue flushing */
+#else
+        WORK_STRUCT_COLOR_SHIFT = 3,    /* color for workqueue flushing */
+#endif
+
+        WORK_STRUCT_COLOR_BITS  = 4,
+
+        WORK_STRUCT_PENDING     = 1 << WORK_STRUCT_PENDING_BIT,
+        WORK_STRUCT_CWQ         = 1 << WORK_STRUCT_CWQ_BIT,
+        WORK_STRUCT_LINKED      = 1 << WORK_STRUCT_LINKED_BIT,
+#ifdef CONFIG_DEBUG_OBJECTS_WORK
+        WORK_STRUCT_STATIC      = 1 << WORK_STRUCT_STATIC_BIT,
+#else
+        WORK_STRUCT_STATIC      = 0,
+#endif
+
+        /*
+         * The last color is no color used for works which don't
+         * participate in workqueue flushing.
+         */
+        WORK_NR_COLORS          = (1 << WORK_STRUCT_COLOR_BITS) - 1,
+        WORK_NO_COLOR           = WORK_NR_COLORS,
+
+        /* special cpu IDs */
+        WORK_CPU_UNBOUND        = NR_CPUS,
+        WORK_CPU_NONE           = NR_CPUS + 1,
+        WORK_CPU_LAST           = WORK_CPU_NONE,
+
+        /*
+         * Reserve 7 bits off of cwq pointer w/ debugobjects turned
+         * off.  This makes cwqs aligned to 128 bytes which isn't too
+         * excessive while allowing 15 workqueue flush colors.
+         */
+        WORK_STRUCT_FLAG_BITS   = WORK_STRUCT_COLOR_SHIFT +
+                                  WORK_STRUCT_COLOR_BITS,
+
+        WORK_STRUCT_FLAG_MASK   = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
+        WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
+        WORK_STRUCT_NO_CPU      = WORK_CPU_NONE << WORK_STRUCT_FLAG_BITS,
+
+        /* bit mask for work_busy() return values */
+        WORK_BUSY_PENDING       = 1 << 0,
+        WORK_BUSY_RUNNING       = 1 << 1,
+};
+
 struct work_struct {
         atomic_long_t data;
-#define WORK_STRUCT_PENDING 0           /* T if work item pending execution */
-#define WORK_STRUCT_STATIC  1           /* static initializer (debugobjects) */
-#define WORK_STRUCT_FLAG_MASK (3UL)
-#define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK)
         struct list_head entry;
         work_func_t func;
 #ifdef CONFIG_LOCKDEP
@@ -35,8 +83,9 @@ struct work_struct {
 #endif
 };
 
-#define WORK_DATA_INIT()        ATOMIC_LONG_INIT(0)
-#define WORK_DATA_STATIC_INIT() ATOMIC_LONG_INIT(2)
+#define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU)
+#define WORK_DATA_STATIC_INIT() \
+        ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU | WORK_STRUCT_STATIC)
 
 struct delayed_work {
         struct work_struct work;
@@ -96,9 +145,14 @@ struct execute_work {
 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 extern void __init_work(struct work_struct *work, int onstack);
 extern void destroy_work_on_stack(struct work_struct *work);
+static inline unsigned int work_static(struct work_struct *work)
+{
+        return *work_data_bits(work) & WORK_STRUCT_STATIC;
+}
 #else
 static inline void __init_work(struct work_struct *work, int onstack) { }
 static inline void destroy_work_on_stack(struct work_struct *work) { }
+static inline unsigned int work_static(struct work_struct *work) { return 0; }
 #endif
 
 /*
@@ -162,7 +216,7 @@ static inline void destroy_work_on_stack(struct work_struct *work) { }
  * @work: The work item in question
  */
 #define work_pending(work) \
-        test_bit(WORK_STRUCT_PENDING, work_data_bits(work))
+        test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 
 /**
  * delayed_work_pending - Find out whether a delayable work item is currently
@@ -177,16 +231,56 @@ static inline void destroy_work_on_stack(struct work_struct *work) { }
  * @work: The work item in question
  */
 #define work_clear_pending(work) \
-        clear_bit(WORK_STRUCT_PENDING, work_data_bits(work))
+        clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
+
+enum {
+        WQ_NON_REENTRANT        = 1 << 0, /* guarantee non-reentrance */
+        WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
+        WQ_FREEZEABLE           = 1 << 2, /* freeze during suspend */
+        WQ_RESCUER              = 1 << 3, /* has an rescue worker */
+        WQ_HIGHPRI              = 1 << 4, /* high priority */
+        WQ_CPU_INTENSIVE        = 1 << 5, /* cpu instensive workqueue */
+
+        WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
+        WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
+        WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
+};
+
+/* unbound wq's aren't per-cpu, scale max_active according to #cpus */
+#define WQ_UNBOUND_MAX_ACTIVE   \
+        max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 
+/*
+ * System-wide workqueues which are always present.
+ *
+ * system_wq is the one used by schedule[_delayed]_work[_on]().
+ * Multi-CPU multi-threaded.  There are users which expect relatively
+ * short queue flush time.  Don't queue works which can run for too
+ * long.
+ *
+ * system_long_wq is similar to system_wq but may host long running
+ * works.  Queue flushing might take relatively long.
+ *
+ * system_nrt_wq is non-reentrant and guarantees that any given work
+ * item is never executed in parallel by multiple CPUs.  Queue
+ * flushing might take relatively long.
+ *
+ * system_unbound_wq is unbound workqueue.  Workers are not bound to
+ * any specific CPU, not concurrency managed, and all queued works are
+ * executed immediately as long as max_active limit is not reached and
+ * resources are available.
+ */
+extern struct workqueue_struct *system_wq;
+extern struct workqueue_struct *system_long_wq;
+extern struct workqueue_struct *system_nrt_wq;
+extern struct workqueue_struct *system_unbound_wq;
 
 extern struct workqueue_struct *
-__create_workqueue_key(const char *name, int singlethread,
-                       int freezeable, int rt, struct lock_class_key *key,
-                       const char *lock_name);
+__alloc_workqueue_key(const char *name, unsigned int flags, int max_active,
+                      struct lock_class_key *key, const char *lock_name);
 
 #ifdef CONFIG_LOCKDEP
-#define __create_workqueue(name, singlethread, freezeable, rt)  \
+#define alloc_workqueue(name, flags, max_active)                \
 ({                                                              \
         static struct lock_class_key __key;                     \
         const char *__lock_name;                                \
@@ -196,20 +290,20 @@ __create_workqueue_key(const char *name, int singlethread,
         else                                                    \
                 __lock_name = #name;                            \
                                                                 \
-        __create_workqueue_key((name), (singlethread),          \
-                               (freezeable), (rt), &__key,      \
-                               __lock_name);                    \
+        __alloc_workqueue_key((name), (flags), (max_active),    \
+                              &__key, __lock_name);             \
 })
 #else
-#define __create_workqueue(name, singlethread, freezeable, rt)  \
-        __create_workqueue_key((name), (singlethread), (freezeable), (rt), \
-                               NULL, NULL)
+#define alloc_workqueue(name, flags, max_active)                \
+        __alloc_workqueue_key((name), (flags), (max_active), NULL, NULL)
 #endif
 
-#define create_workqueue(name) __create_workqueue((name), 0, 0, 0)
-#define create_rt_workqueue(name) __create_workqueue((name), 0, 0, 1)
-#define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1, 0)
-#define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0, 0)
+#define create_workqueue(name)                                  \
+        alloc_workqueue((name), WQ_RESCUER, 1)
+#define create_freezeable_workqueue(name)                       \
+        alloc_workqueue((name), WQ_FREEZEABLE | WQ_UNBOUND | WQ_RESCUER, 1)
+#define create_singlethread_workqueue(name)                     \
+        alloc_workqueue((name), WQ_UNBOUND | WQ_RESCUER, 1)
 
 extern void destroy_workqueue(struct workqueue_struct *wq);
 
@@ -231,16 +325,19 @@ extern int schedule_delayed_work(struct delayed_work *work, unsigned long delay)
 extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
                                         unsigned long delay);
 extern int schedule_on_each_cpu(work_func_t func);
-extern int current_is_keventd(void);
 extern int keventd_up(void);
 
-extern void init_workqueues(void);
 int execute_in_process_context(work_func_t fn, struct execute_work *);
 
 extern int flush_work(struct work_struct *work);
-
 extern int cancel_work_sync(struct work_struct *work);
 
+extern void workqueue_set_max_active(struct workqueue_struct *wq,
+                                     int max_active);
+extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq);
+extern unsigned int work_cpu(struct work_struct *work);
+extern unsigned int work_busy(struct work_struct *work);
+
 /*
  * Kill off a pending schedule_delayed_work().  Note that the work callback
  * function may still be running on return from cancel_delayed_work(), unless
@@ -298,7 +395,14 @@ static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
 long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);
 #endif /* CONFIG_SMP */
 
+#ifdef CONFIG_FREEZER
+extern void freeze_workqueues_begin(void);
+extern bool freeze_workqueues_busy(void);
+extern void thaw_workqueues(void);
+#endif /* CONFIG_FREEZER */
+
 #ifdef CONFIG_LOCKDEP
 int in_workqueue_context(struct workqueue_struct *wq);
 #endif
+
 #endif
diff --git a/include/trace/events/workqueue.h b/include/trace/events/workqueue.h
deleted file mode 100644
index d6c974474e70..000000000000
--- a/include/trace/events/workqueue.h
+++ /dev/null
@@ -1,92 +0,0 @@
-#undef TRACE_SYSTEM
-#define TRACE_SYSTEM workqueue
-
-#if !defined(_TRACE_WORKQUEUE_H) || defined(TRACE_HEADER_MULTI_READ)
-#define _TRACE_WORKQUEUE_H
-
-#include <linux/workqueue.h>
-#include <linux/sched.h>
-#include <linux/tracepoint.h>
-
-DECLARE_EVENT_CLASS(workqueue,
-
-        TP_PROTO(struct task_struct *wq_thread, struct work_struct *work),
-
-        TP_ARGS(wq_thread, work),
-
-        TP_STRUCT__entry(
-                __array(char,           thread_comm,    TASK_COMM_LEN)
-                __field(pid_t,          thread_pid)
-                __field(work_func_t,    func)
-        ),
-
-        TP_fast_assign(
-                memcpy(__entry->thread_comm, wq_thread->comm, TASK_COMM_LEN);
-                __entry->thread_pid     = wq_thread->pid;
-                __entry->func           = work->func;
-        ),
-
-        TP_printk("thread=%s:%d func=%pf", __entry->thread_comm,
-                __entry->thread_pid, __entry->func)
-);
-
-DEFINE_EVENT(workqueue, workqueue_insertion,
-
-        TP_PROTO(struct task_struct *wq_thread, struct work_struct *work),
-
-        TP_ARGS(wq_thread, work)
-);
-
-DEFINE_EVENT(workqueue, workqueue_execution,
-
-        TP_PROTO(struct task_struct *wq_thread, struct work_struct *work),
-
-        TP_ARGS(wq_thread, work)
-);
-
-/* Trace the creation of one workqueue thread on a cpu */
-TRACE_EVENT(workqueue_creation,
-
-        TP_PROTO(struct task_struct *wq_thread, int cpu),
-
-        TP_ARGS(wq_thread, cpu),
-
-        TP_STRUCT__entry(
-                __array(char,   thread_comm,    TASK_COMM_LEN)
-                __field(pid_t,  thread_pid)
-                __field(int,    cpu)
-        ),
-
-        TP_fast_assign(
-                memcpy(__entry->thread_comm, wq_thread->comm, TASK_COMM_LEN);
-                __entry->thread_pid     = wq_thread->pid;
-                __entry->cpu            = cpu;
-        ),
-
-        TP_printk("thread=%s:%d cpu=%d", __entry->thread_comm,
-                __entry->thread_pid, __entry->cpu)
-);
-
-TRACE_EVENT(workqueue_destruction,
-
-        TP_PROTO(struct task_struct *wq_thread),
-
-        TP_ARGS(wq_thread),
-
-        TP_STRUCT__entry(
-                __array(char,   thread_comm,    TASK_COMM_LEN)
-                __field(pid_t,  thread_pid)
-        ),
-
-        TP_fast_assign(
-                memcpy(__entry->thread_comm, wq_thread->comm, TASK_COMM_LEN);
-                __entry->thread_pid     = wq_thread->pid;
-        ),
-
-        TP_printk("thread=%s:%d", __entry->thread_comm, __entry->thread_pid)
-);
-
-#endif /* _TRACE_WORKQUEUE_H */
-
-/* This part must be outside protection */
-#include <trace/define_trace.h>
diff --git a/init/Kconfig b/init/Kconfig
index 5cff9a980c39..cb64c5889e02 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1143,30 +1143,6 @@ config TRACEPOINTS
 
 source "arch/Kconfig"
 
-config SLOW_WORK
-        default n
-        bool
-        help
-          The slow work thread pool provides a number of dynamically allocated
-          threads that can be used by the kernel to perform operations that
-          take a relatively long time.
-
-          An example of this would be CacheFiles doing a path lookup followed
-          by a series of mkdirs and a create call, all of which have to touch
-          disk.
-
-          See Documentation/slow-work.txt.
-
-config SLOW_WORK_DEBUG
-        bool "Slow work debugging through debugfs"
-        default n
-        depends on SLOW_WORK && DEBUG_FS
-        help
-          Display the contents of the slow work run queue through debugfs,
-          including items currently executing.
-
-          See Documentation/slow-work.txt.
-
 endmenu         # General setup
 
 config HAVE_GENERIC_DMA_COHERENT
diff --git a/init/main.c b/init/main.c
index b03a4c1f69fa..e97fadeec856 100644
--- a/init/main.c
+++ b/init/main.c
@@ -32,7 +32,6 @@
 #include <linux/start_kernel.h>
 #include <linux/security.h>
 #include <linux/smp.h>
-#include <linux/workqueue.h>
 #include <linux/profile.h>
 #include <linux/rcupdate.h>
 #include <linux/moduleparam.h>
@@ -789,7 +788,6 @@ static void __init do_initcalls(void)
  */
 static void __init do_basic_setup(void)
 {
-        init_workqueues();
         cpuset_init_smp();
         usermodehelper_init();
         init_tmpfs();
diff --git a/kernel/Makefile b/kernel/Makefile
index ce53fb2bd1d9..c53e491e25a8 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -99,8 +99,6 @@ obj-$(CONFIG_TRACING) += trace/
 obj-$(CONFIG_X86_DS) += trace/
 obj-$(CONFIG_RING_BUFFER) += trace/
 obj-$(CONFIG_SMP) += sched_cpupri.o
-obj-$(CONFIG_SLOW_WORK) += slow-work.o
-obj-$(CONFIG_SLOW_WORK_DEBUG) += slow-work-debugfs.o
 obj-$(CONFIG_PERF_EVENTS) += perf_event.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
 obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
diff --git a/kernel/async.c b/kernel/async.c
index 15319d6c18fe..cd9dbb913c77 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -49,40 +49,33 @@ asynchronous and synchronous parts of the kernel.
 */
 
 #include <linux/async.h>
-#include <linux/bug.h>
 #include <linux/module.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/kthread.h>
-#include <linux/delay.h>
 #include <linux/slab.h>
+#include <linux/workqueue.h>
 #include <asm/atomic.h>
 
 static async_cookie_t next_cookie = 1;
 
-#define MAX_THREADS     256
 #define MAX_WORK        32768
 
 static LIST_HEAD(async_pending);
 static LIST_HEAD(async_running);
 static DEFINE_SPINLOCK(async_lock);
 
-static int async_enabled = 0;
-
 struct async_entry {
-        struct list_head list;
-        async_cookie_t   cookie;
-        async_func_ptr   *func;
-        void             *data;
-        struct list_head *running;
+        struct list_head        list;
+        struct work_struct      work;
+        async_cookie_t          cookie;
+        async_func_ptr          *func;
+        void                    *data;
+        struct list_head        *running;
 };
 
 static DECLARE_WAIT_QUEUE_HEAD(async_done);
-static DECLARE_WAIT_QUEUE_HEAD(async_new);
 
 static atomic_t entry_count;
-static atomic_t thread_count;
 
 extern int initcall_debug;
 
@@ -117,27 +110,23 @@ static async_cookie_t  lowest_in_progress(struct list_head *running)
         spin_unlock_irqrestore(&async_lock, flags);
         return ret;
 }
+
 /*
  * pick the first pending entry and run it
  */
-static void run_one_entry(void)
+static void async_run_entry_fn(struct work_struct *work)
 {
+        struct async_entry *entry =
+                container_of(work, struct async_entry, work);
         unsigned long flags;
-        struct async_entry *entry;
         ktime_t calltime, delta, rettime;
 
-        /* 1) pick one task from the pending queue */
-
+        /* 1) move self to the running queue */
         spin_lock_irqsave(&async_lock, flags);
-        if (list_empty(&async_pending))
-                goto out;
-        entry = list_first_entry(&async_pending, struct async_entry, list);
-
-        /* 2) move it to the running queue */
         list_move_tail(&entry->list, entry->running);
         spin_unlock_irqrestore(&async_lock, flags);
 
-        /* 3) run it (and print duration)*/
+        /* 2) run (and print duration) */
         if (initcall_debug && system_state == SYSTEM_BOOTING) {
                 printk("calling  %lli_%pF @ %i\n", (long long)entry->cookie,
                         entry->func, task_pid_nr(current));
@@ -153,31 +142,25 @@ static void run_one_entry(void)
                         (long long)ktime_to_ns(delta) >> 10);
         }
 
-        /* 4) remove it from the running queue */
+        /* 3) remove self from the running queue */
         spin_lock_irqsave(&async_lock, flags);
         list_del(&entry->list);
 
-        /* 5) free the entry  */
+        /* 4) free the entry */
         kfree(entry);
         atomic_dec(&entry_count);
 
         spin_unlock_irqrestore(&async_lock, flags);
 
-        /* 6) wake up any waiters. */
+        /* 5) wake up any waiters */
         wake_up(&async_done);
-        return;
-
-out:
-        spin_unlock_irqrestore(&async_lock, flags);
 }
 
-
 static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct list_head *running)
 {
         struct async_entry *entry;
         unsigned long flags;
         async_cookie_t newcookie;
-        
 
         /* allow irq-off callers */
         entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
@@ -186,7 +169,7 @@ static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct l
          * If we're out of memory or if there's too much work
          * pending already, we execute synchronously.
          */
-        if (!async_enabled || !entry || atomic_read(&entry_count) > MAX_WORK) {
+        if (!entry || atomic_read(&entry_count) > MAX_WORK) {
                 kfree(entry);
                 spin_lock_irqsave(&async_lock, flags);
                 newcookie = next_cookie++;
@@ -196,6 +179,7 @@ static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct l
                 ptr(data, newcookie);
                 return newcookie;
         }
+        INIT_WORK(&entry->work, async_run_entry_fn);
         entry->func = ptr;
         entry->data = data;
         entry->running = running;
@@ -205,7 +189,10 @@ static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct l
         list_add_tail(&entry->list, &async_pending);
         atomic_inc(&entry_count);
         spin_unlock_irqrestore(&async_lock, flags);
-        wake_up(&async_new);
+
+        /* schedule for execution */
+        queue_work(system_unbound_wq, &entry->work);
+
         return newcookie;
 }
 
@@ -312,87 +299,3 @@ void async_synchronize_cookie(async_cookie_t cookie)
         async_synchronize_cookie_domain(cookie, &async_running);
 }
 EXPORT_SYMBOL_GPL(async_synchronize_cookie);
-
-
-static int async_thread(void *unused)
-{
-        DECLARE_WAITQUEUE(wq, current);
-        add_wait_queue(&async_new, &wq);
-
-        while (!kthread_should_stop()) {
-                int ret = HZ;
-                set_current_state(TASK_INTERRUPTIBLE);
-                /*
-                 * check the list head without lock.. false positives
-                 * are dealt with inside run_one_entry() while holding
-                 * the lock.
-                 */
-                rmb();
-                if (!list_empty(&async_pending))
-                        run_one_entry();
-                else
-                        ret = schedule_timeout(HZ);
-
-                if (ret == 0) {
-                        /*
-                         * we timed out, this means we as thread are redundant.
-                         * we sign off and die, but we to avoid any races there
-                         * is a last-straw check to see if work snuck in.
-                         */
-                        atomic_dec(&thread_count);
-                        wmb(); /* manager must see our departure first */
-                        if (list_empty(&async_pending))
-                                break;
-                        /*
-                         * woops work came in between us timing out and us
-                         * signing off; we need to stay alive and keep working.
-                         */
-                        atomic_inc(&thread_count);
-                }
-        }
-        remove_wait_queue(&async_new, &wq);
-
-        return 0;
-}
-
-static int async_manager_thread(void *unused)
-{
-        DECLARE_WAITQUEUE(wq, current);
-        add_wait_queue(&async_new, &wq);
-
-        while (!kthread_should_stop()) {
-                int tc, ec;
-
-                set_current_state(TASK_INTERRUPTIBLE);
-
-                tc = atomic_read(&thread_count);
-                rmb();
-                ec = atomic_read(&entry_count);
-
-                while (tc < ec && tc < MAX_THREADS) {
-                        if (IS_ERR(kthread_run(async_thread, NULL, "async/%i",
-                                               tc))) {
-                                msleep(100);
-                                continue;
-                        }
-                        atomic_inc(&thread_count);
-                        tc++;
-                }
-
-                schedule();
-        }
-        remove_wait_queue(&async_new, &wq);
-
-        return 0;
-}
-
-static int __init async_init(void)
-{
-        async_enabled =
-                !IS_ERR(kthread_run(async_manager_thread, NULL, "async/mgr"));
-
-        WARN_ON(!async_enabled);
-        return 0;
-}
-
-core_initcall(async_init);
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 83911c780175..2dc3786349d1 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -14,6 +14,8 @@
 #include <linux/file.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/freezer.h>
 #include <trace/events/sched.h>
 
 static DEFINE_SPINLOCK(kthread_create_lock);
@@ -35,6 +37,7 @@ struct kthread_create_info
 
 struct kthread {
         int should_stop;
+        void *data;
         struct completion exited;
 };
 
@@ -54,6 +57,19 @@ int kthread_should_stop(void)
 }
 EXPORT_SYMBOL(kthread_should_stop);
 
+/**
+ * kthread_data - return data value specified on kthread creation
+ * @task: kthread task in question
+ *
+ * Return the data value specified when kthread @task was created.
+ * The caller is responsible for ensuring the validity of @task when
+ * calling this function.
+ */
+void *kthread_data(struct task_struct *task)
+{
+        return to_kthread(task)->data;
+}
+
 static int kthread(void *_create)
 {
         /* Copy data: it's on kthread's stack */
@@ -64,6 +80,7 @@ static int kthread(void *_create)
         int ret;
 
         self.should_stop = 0;
+        self.data = data;
         init_completion(&self.exited);
         current->vfork_done = &self.exited;
 
@@ -247,3 +264,150 @@ int kthreadd(void *unused)
 
         return 0;
 }
+
+/**
+ * kthread_worker_fn - kthread function to process kthread_worker
+ * @worker_ptr: pointer to initialized kthread_worker
+ *
+ * This function can be used as @threadfn to kthread_create() or
+ * kthread_run() with @worker_ptr argument pointing to an initialized
+ * kthread_worker.  The started kthread will process work_list until
+ * the it is stopped with kthread_stop().  A kthread can also call
+ * this function directly after extra initialization.
+ *
+ * Different kthreads can be used for the same kthread_worker as long
+ * as there's only one kthread attached to it at any given time.  A
+ * kthread_worker without an attached kthread simply collects queued
+ * kthread_works.
+ */
+int kthread_worker_fn(void *worker_ptr)
+{
+        struct kthread_worker *worker = worker_ptr;
+        struct kthread_work *work;
+
+        WARN_ON(worker->task);
+        worker->task = current;
+repeat:
+        set_current_state(TASK_INTERRUPTIBLE);  /* mb paired w/ kthread_stop */
+
+        if (kthread_should_stop()) {
+                __set_current_state(TASK_RUNNING);
+                spin_lock_irq(&worker->lock);
+                worker->task = NULL;
+                spin_unlock_irq(&worker->lock);
+                return 0;
+        }
+
+        work = NULL;
+        spin_lock_irq(&worker->lock);
+        if (!list_empty(&worker->work_list)) {
+                work = list_first_entry(&worker->work_list,
+                                        struct kthread_work, node);
+                list_del_init(&work->node);
+        }
+        spin_unlock_irq(&worker->lock);
+
+        if (work) {
+                __set_current_state(TASK_RUNNING);
+                work->func(work);
+                smp_wmb();      /* wmb worker-b0 paired with flush-b1 */
+                work->done_seq = work->queue_seq;
+                smp_mb();       /* mb worker-b1 paired with flush-b0 */
+                if (atomic_read(&work->flushing))
+                        wake_up_all(&work->done);
+        } else if (!freezing(current))
+                schedule();
+
+        try_to_freeze();
+        goto repeat;
+}
+EXPORT_SYMBOL_GPL(kthread_worker_fn);
+
+/**
+ * queue_kthread_work - queue a kthread_work
+ * @worker: target kthread_worker
+ * @work: kthread_work to queue
+ *
+ * Queue @work to work processor @task for async execution.  @task
+ * must have been created with kthread_worker_create().  Returns %true
+ * if @work was successfully queued, %false if it was already pending.
+ */
+bool queue_kthread_work(struct kthread_worker *worker,
+                        struct kthread_work *work)
+{
+        bool ret = false;
+        unsigned long flags;
+
+        spin_lock_irqsave(&worker->lock, flags);
+        if (list_empty(&work->node)) {
+                list_add_tail(&work->node, &worker->work_list);
+                work->queue_seq++;
+                if (likely(worker->task))
+                        wake_up_process(worker->task);
+                ret = true;
+        }
+        spin_unlock_irqrestore(&worker->lock, flags);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(queue_kthread_work);
+
+/**
+ * flush_kthread_work - flush a kthread_work
+ * @work: work to flush
+ *
+ * If @work is queued or executing, wait for it to finish execution.
+ */
+void flush_kthread_work(struct kthread_work *work)
+{
+        int seq = work->queue_seq;
+
+        atomic_inc(&work->flushing);
+
+        /*
+         * mb flush-b0 paired with worker-b1, to make sure either
+         * worker sees the above increment or we see done_seq update.
+         */
+        smp_mb__after_atomic_inc();
+
+        /* A - B <= 0 tests whether B is in front of A regardless of overflow */
+        wait_event(work->done, seq - work->done_seq <= 0);
+        atomic_dec(&work->flushing);
+
+        /*
+         * rmb flush-b1 paired with worker-b0, to make sure our caller
+         * sees every change made by work->func().
+         */
+        smp_mb__after_atomic_dec();
+}
+EXPORT_SYMBOL_GPL(flush_kthread_work);
+
+struct kthread_flush_work {
+        struct kthread_work     work;
+        struct completion       done;
+};
+
+static void kthread_flush_work_fn(struct kthread_work *work)
+{
+        struct kthread_flush_work *fwork =
+                container_of(work, struct kthread_flush_work, work);
+        complete(&fwork->done);
+}
+
+/**
+ * flush_kthread_worker - flush all current works on a kthread_worker
+ * @worker: worker to flush
+ *
+ * Wait until all currently executing or pending works on @worker are
+ * finished.
+ */
+void flush_kthread_worker(struct kthread_worker *worker)
+{
+        struct kthread_flush_work fwork = {
+                KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
+                COMPLETION_INITIALIZER_ONSTACK(fwork.done),
+        };
+
+        queue_kthread_work(worker, &fwork.work);
+        wait_for_completion(&fwork.done);
+}
+EXPORT_SYMBOL_GPL(flush_kthread_worker);
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 71ae29052ab6..028a99598f49 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -15,6 +15,7 @@
 #include <linux/syscalls.h>
 #include <linux/freezer.h>
 #include <linux/delay.h>
+#include <linux/workqueue.h>
 
 /* 
  * Timeout for stopping processes
@@ -35,6 +36,7 @@ static int try_to_freeze_tasks(bool sig_only)
         struct task_struct *g, *p;
         unsigned long end_time;
         unsigned int todo;
+        bool wq_busy = false;
         struct timeval start, end;
         u64 elapsed_csecs64;
         unsigned int elapsed_csecs;
@@ -42,6 +44,10 @@ static int try_to_freeze_tasks(bool sig_only)
         do_gettimeofday(&start);
 
         end_time = jiffies + TIMEOUT;
+
+        if (!sig_only)
+                freeze_workqueues_begin();
+
         while (true) {
                 todo = 0;
                 read_lock(&tasklist_lock);
@@ -63,6 +69,12 @@ static int try_to_freeze_tasks(bool sig_only)
                                 todo++;
                 } while_each_thread(g, p);
                 read_unlock(&tasklist_lock);
+
+                if (!sig_only) {
+                        wq_busy = freeze_workqueues_busy();
+                        todo += wq_busy;
+                }
+
                 if (!todo || time_after(jiffies, end_time))
                         break;
 
@@ -86,8 +98,12 @@ static int try_to_freeze_tasks(bool sig_only)
                  */
                 printk("\n");
                 printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "
-                                "(%d tasks refusing to freeze):\n",
-                                elapsed_csecs / 100, elapsed_csecs % 100, todo);
+                       "(%d tasks refusing to freeze, wq_busy=%d):\n",
+                       elapsed_csecs / 100, elapsed_csecs % 100,
+                       todo - wq_busy, wq_busy);
+
+                thaw_workqueues();
+
                 read_lock(&tasklist_lock);
                 do_each_thread(g, p) {
                         task_lock(p);
@@ -157,6 +173,7 @@ void thaw_processes(void)
         oom_killer_enable();
 
         printk("Restarting tasks ... ");
+        thaw_workqueues();
         thaw_tasks(true);
         thaw_tasks(false);
         schedule();
diff --git a/kernel/slow-work-debugfs.c b/kernel/slow-work-debugfs.c
deleted file mode 100644
index e45c43645298..000000000000
--- a/kernel/slow-work-debugfs.c
+++ /dev/null
@@ -1,227 +0,0 @@
-/* Slow work debugging
- *
- * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-
-#include <linux/module.h>
-#include <linux/slow-work.h>
-#include <linux/fs.h>
-#include <linux/time.h>
-#include <linux/seq_file.h>
-#include "slow-work.h"
-
-#define ITERATOR_SHIFT          (BITS_PER_LONG - 4)
-#define ITERATOR_SELECTOR       (0xfUL << ITERATOR_SHIFT)
-#define ITERATOR_COUNTER        (~ITERATOR_SELECTOR)
-
-void slow_work_new_thread_desc(struct slow_work *work, struct seq_file *m)
-{
-        seq_puts(m, "Slow-work: New thread");
-}
-
-/*
- * Render the time mark field on a work item into a 5-char time with units plus
- * a space
- */
-static void slow_work_print_mark(struct seq_file *m, struct slow_work *work)
-{
-        struct timespec now, diff;
-
-        now = CURRENT_TIME;
-        diff = timespec_sub(now, work->mark);
-
-        if (diff.tv_sec < 0)
-                seq_puts(m, "  -ve ");
-        else if (diff.tv_sec == 0 && diff.tv_nsec < 1000)
-                seq_printf(m, "%3luns ", diff.tv_nsec);
-        else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000)
-                seq_printf(m, "%3luus ", diff.tv_nsec / 1000);
-        else if (diff.tv_sec == 0 && diff.tv_nsec < 1000000000)
-                seq_printf(m, "%3lums ", diff.tv_nsec / 1000000);
-        else if (diff.tv_sec <= 1)
-                seq_puts(m, "   1s ");
-        else if (diff.tv_sec < 60)
-                seq_printf(m, "%4lus ", diff.tv_sec);
-        else if (diff.tv_sec < 60 * 60)
-                seq_printf(m, "%4lum ", diff.tv_sec / 60);
-        else if (diff.tv_sec < 60 * 60 * 24)
-                seq_printf(m, "%4luh ", diff.tv_sec / 3600);
-        else
-                seq_puts(m, "exces ");
-}
-
-/*
- * Describe a slow work item for debugfs
- */
-static int slow_work_runqueue_show(struct seq_file *m, void *v)
-{
-        struct slow_work *work;
-        struct list_head *p = v;
-        unsigned long id;
-
-        switch ((unsigned long) v) {
-        case 1:
-                seq_puts(m, "THR PID   ITEM ADDR        FL MARK  DESC\n");
-                return 0;
-        case 2:
-                seq_puts(m, "=== ===== ================ == ===== ==========\n");
-                return 0;
-
-        case 3 ... 3 + SLOW_WORK_THREAD_LIMIT - 1:
-                id = (unsigned long) v - 3;
-
-                read_lock(&slow_work_execs_lock);
-                work = slow_work_execs[id];
-                if (work) {
-                        smp_read_barrier_depends();
-
-                        seq_printf(m, "%3lu %5d %16p %2lx ",
-                                   id, slow_work_pids[id], work, work->flags);
-                        slow_work_print_mark(m, work);
-
-                        if (work->ops->desc)
-                                work->ops->desc(work, m);
-                        seq_putc(m, '\n');
-                }
-                read_unlock(&slow_work_execs_lock);
-                return 0;
-
-        default:
-                work = list_entry(p, struct slow_work, link);
-                seq_printf(m, "%3s     - %16p %2lx ",
-                           work->flags & SLOW_WORK_VERY_SLOW ? "vsq" : "sq",
-                           work, work->flags);
-                slow_work_print_mark(m, work);
-
-                if (work->ops->desc)
-                        work->ops->desc(work, m);
-                seq_putc(m, '\n');
-                return 0;
-        }
-}
-
-/*
- * map the iterator to a work item
- */
-static void *slow_work_runqueue_index(struct seq_file *m, loff_t *_pos)
-{
-        struct list_head *p;
-        unsigned long count, id;
-
-        switch (*_pos >> ITERATOR_SHIFT) {
-        case 0x0:
-                if (*_pos == 0)
-                        *_pos = 1;
-                if (*_pos < 3)
-                        return (void *)(unsigned long) *_pos;
-                if (*_pos < 3 + SLOW_WORK_THREAD_LIMIT)
-                        for (id = *_pos - 3;
-                             id < SLOW_WORK_THREAD_LIMIT;
-                             id++, (*_pos)++)
-                                if (slow_work_execs[id])
-                                        return (void *)(unsigned long) *_pos;
-                *_pos = 0x1UL << ITERATOR_SHIFT;
-
-        case 0x1:
-                count = *_pos & ITERATOR_COUNTER;
-                list_for_each(p, &slow_work_queue) {
-                        if (count == 0)
-                                return p;
-                        count--;
-                }
-                *_pos = 0x2UL << ITERATOR_SHIFT;
-
-        case 0x2:
-                count = *_pos & ITERATOR_COUNTER;
-                list_for_each(p, &vslow_work_queue) {
-                        if (count == 0)
-                                return p;
-                        count--;
-                }
-                *_pos = 0x3UL << ITERATOR_SHIFT;
-
-        default:
-                return NULL;
-        }
-}
-
-/*
- * set up the iterator to start reading from the first line
- */
-static void *slow_work_runqueue_start(struct seq_file *m, loff_t *_pos)
-{
-        spin_lock_irq(&slow_work_queue_lock);
-        return slow_work_runqueue_index(m, _pos);
-}
-
-/*
- * move to the next line
- */
-static void *slow_work_runqueue_next(struct seq_file *m, void *v, loff_t *_pos)
-{
-        struct list_head *p = v;
-        unsigned long selector = *_pos >> ITERATOR_SHIFT;
-
-        (*_pos)++;
-        switch (selector) {
-        case 0x0:
-                return slow_work_runqueue_index(m, _pos);
-
-        case 0x1:
-                if (*_pos >> ITERATOR_SHIFT == 0x1) {
-                        p = p->next;
-                        if (p != &slow_work_queue)
-                                return p;
-                }
-                *_pos = 0x2UL << ITERATOR_SHIFT;
-                p = &vslow_work_queue;
-
-        case 0x2:
-                if (*_pos >> ITERATOR_SHIFT == 0x2) {
-                        p = p->next;
-                        if (p != &vslow_work_queue)
-                                return p;
-                }
-                *_pos = 0x3UL << ITERATOR_SHIFT;
-
-        default:
-                return NULL;
-        }
-}
-
-/*
- * clean up after reading
- */
-static void slow_work_runqueue_stop(struct seq_file *m, void *v)
-{
-        spin_unlock_irq(&slow_work_queue_lock);
-}
-
-static const struct seq_operations slow_work_runqueue_ops = {
-        .start          = slow_work_runqueue_start,
-        .stop           = slow_work_runqueue_stop,
-        .next           = slow_work_runqueue_next,
-        .show           = slow_work_runqueue_show,
-};
-
-/*
- * open "/sys/kernel/debug/slow_work/runqueue" to list queue contents
- */
-static int slow_work_runqueue_open(struct inode *inode, struct file *file)
-{
-        return seq_open(file, &slow_work_runqueue_ops);
-}
-
-const struct file_operations slow_work_runqueue_fops = {
-        .owner          = THIS_MODULE,
-        .open           = slow_work_runqueue_open,
-        .read           = seq_read,
-        .llseek         = seq_lseek,
-        .release        = seq_release,
-};
diff --git a/kernel/slow-work.c b/kernel/slow-work.c
deleted file mode 100644
index 7d3f4fa9ef4f..000000000000
--- a/kernel/slow-work.c
+++ /dev/null
@@ -1,1068 +0,0 @@
-/* Worker thread pool for slow items, such as filesystem lookups or mkdirs
- *
- * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- *
- * See Documentation/slow-work.txt
- */
-
-#include <linux/module.h>
-#include <linux/slow-work.h>
-#include <linux/kthread.h>
-#include <linux/freezer.h>
-#include <linux/wait.h>
-#include <linux/debugfs.h>
-#include "slow-work.h"
-
-static void slow_work_cull_timeout(unsigned long);
-static void slow_work_oom_timeout(unsigned long);
-
-#ifdef CONFIG_SYSCTL
-static int slow_work_min_threads_sysctl(struct ctl_table *, int,
-                                        void __user *, size_t *, loff_t *);
-
-static int slow_work_max_threads_sysctl(struct ctl_table *, int ,
-                                        void __user *, size_t *, loff_t *);
-#endif
-
-/*
- * The pool of threads has at least min threads in it as long as someone is
- * using the facility, and may have as many as max.
- *
- * A portion of the pool may be processing very slow operations.
- */
-static unsigned slow_work_min_threads = 2;
-static unsigned slow_work_max_threads = 4;
-static unsigned vslow_work_proportion = 50; /* % of threads that may process
-                                             * very slow work */
-
-#ifdef CONFIG_SYSCTL
-static const int slow_work_min_min_threads = 2;
-static int slow_work_max_max_threads = SLOW_WORK_THREAD_LIMIT;
-static const int slow_work_min_vslow = 1;
-static const int slow_work_max_vslow = 99;
-
-ctl_table slow_work_sysctls[] = {
-        {
-                .procname       = "min-threads",
-                .data           = &slow_work_min_threads,
-                .maxlen         = sizeof(unsigned),
-                .mode           = 0644,
-                .proc_handler   = slow_work_min_threads_sysctl,
-                .extra1         = (void *) &slow_work_min_min_threads,
-                .extra2         = &slow_work_max_threads,
-        },
-        {
-                .procname       = "max-threads",
-                .data           = &slow_work_max_threads,
-                .maxlen         = sizeof(unsigned),
-                .mode           = 0644,
-                .proc_handler   = slow_work_max_threads_sysctl,
-                .extra1         = &slow_work_min_threads,
-                .extra2         = (void *) &slow_work_max_max_threads,
-        },
-        {
-                .procname       = "vslow-percentage",
-                .data           = &vslow_work_proportion,
-                .maxlen         = sizeof(unsigned),
-                .mode           = 0644,
-                .proc_handler   = proc_dointvec_minmax,
-                .extra1         = (void *) &slow_work_min_vslow,
-                .extra2         = (void *) &slow_work_max_vslow,
-        },
-        {}
-};
-#endif
-
-/*
- * The active state of the thread pool
- */
-static atomic_t slow_work_thread_count;
-static atomic_t vslow_work_executing_count;
-
-static bool slow_work_may_not_start_new_thread;
-static bool slow_work_cull; /* cull a thread due to lack of activity */
-static DEFINE_TIMER(slow_work_cull_timer, slow_work_cull_timeout, 0, 0);
-static DEFINE_TIMER(slow_work_oom_timer, slow_work_oom_timeout, 0, 0);
-static struct slow_work slow_work_new_thread; /* new thread starter */
-
-/*
- * slow work ID allocation (use slow_work_queue_lock)
- */
-static DECLARE_BITMAP(slow_work_ids, SLOW_WORK_THREAD_LIMIT);
-
-/*
- * Unregistration tracking to prevent put_ref() from disappearing during module
- * unload
- */
-#ifdef CONFIG_MODULES
-static struct module *slow_work_thread_processing[SLOW_WORK_THREAD_LIMIT];
-static struct module *slow_work_unreg_module;
-static struct slow_work *slow_work_unreg_work_item;
-static DECLARE_WAIT_QUEUE_HEAD(slow_work_unreg_wq);
-static DEFINE_MUTEX(slow_work_unreg_sync_lock);
-
-static void slow_work_set_thread_processing(int id, struct slow_work *work)
-{
-        if (work)
-                slow_work_thread_processing[id] = work->owner;
-}
-static void slow_work_done_thread_processing(int id, struct slow_work *work)
-{
-        struct module *module = slow_work_thread_processing[id];
-
-        slow_work_thread_processing[id] = NULL;
-        smp_mb();
-        if (slow_work_unreg_work_item == work ||
-            slow_work_unreg_module == module)
-                wake_up_all(&slow_work_unreg_wq);
-}
-static void slow_work_clear_thread_processing(int id)
-{
-        slow_work_thread_processing[id] = NULL;
-}
-#else
-static void slow_work_set_thread_processing(int id, struct slow_work *work) {}
-static void slow_work_done_thread_processing(int id, struct slow_work *work) {}
-static void slow_work_clear_thread_processing(int id) {}
-#endif
-
-/*
- * Data for tracking currently executing items for indication through /proc
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-struct slow_work *slow_work_execs[SLOW_WORK_THREAD_LIMIT];
-pid_t slow_work_pids[SLOW_WORK_THREAD_LIMIT];
-DEFINE_RWLOCK(slow_work_execs_lock);
-#endif
-
-/*
- * The queues of work items and the lock governing access to them.  These are
- * shared between all the CPUs.  It doesn't make sense to have per-CPU queues
- * as the number of threads bears no relation to the number of CPUs.
- *
- * There are two queues of work items: one for slow work items, and one for
- * very slow work items.
- */
-LIST_HEAD(slow_work_queue);
-LIST_HEAD(vslow_work_queue);
-DEFINE_SPINLOCK(slow_work_queue_lock);
-
-/*
- * The following are two wait queues that get pinged when a work item is placed
- * on an empty queue.  These allow work items that are hogging a thread by
- * sleeping in a way that could be deferred to yield their thread and enqueue
- * themselves.
- */
-static DECLARE_WAIT_QUEUE_HEAD(slow_work_queue_waits_for_occupation);
-static DECLARE_WAIT_QUEUE_HEAD(vslow_work_queue_waits_for_occupation);
-
-/*
- * The thread controls.  A variable used to signal to the threads that they
- * should exit when the queue is empty, a waitqueue used by the threads to wait
- * for signals, and a completion set by the last thread to exit.
- */
-static bool slow_work_threads_should_exit;
-static DECLARE_WAIT_QUEUE_HEAD(slow_work_thread_wq);
-static DECLARE_COMPLETION(slow_work_last_thread_exited);
-
-/*
- * The number of users of the thread pool and its lock.  Whilst this is zero we
- * have no threads hanging around, and when this reaches zero, we wait for all
- * active or queued work items to complete and kill all the threads we do have.
- */
-static int slow_work_user_count;
-static DEFINE_MUTEX(slow_work_user_lock);
-
-static inline int slow_work_get_ref(struct slow_work *work)
-{
-        if (work->ops->get_ref)
-                return work->ops->get_ref(work);
-
-        return 0;
-}
-
-static inline void slow_work_put_ref(struct slow_work *work)
-{
-        if (work->ops->put_ref)
-                work->ops->put_ref(work);
-}
-
-/*
- * Calculate the maximum number of active threads in the pool that are
- * permitted to process very slow work items.
- *
- * The answer is rounded up to at least 1, but may not equal or exceed the
- * maximum number of the threads in the pool.  This means we always have at
- * least one thread that can process slow work items, and we always have at
- * least one thread that won't get tied up doing so.
- */
-static unsigned slow_work_calc_vsmax(void)
-{
-        unsigned vsmax;
-
-        vsmax = atomic_read(&slow_work_thread_count) * vslow_work_proportion;
-        vsmax /= 100;
-        vsmax = max(vsmax, 1U);
-        return min(vsmax, slow_work_max_threads - 1);
-}
-
-/*
- * Attempt to execute stuff queued on a slow thread.  Return true if we managed
- * it, false if there was nothing to do.
- */
-static noinline bool slow_work_execute(int id)
-{
-        struct slow_work *work = NULL;
-        unsigned vsmax;
-        bool very_slow;
-
-        vsmax = slow_work_calc_vsmax();
-
-        /* see if we can schedule a new thread to be started if we're not
-         * keeping up with the work */
-        if (!waitqueue_active(&slow_work_thread_wq) &&
-            (!list_empty(&slow_work_queue) || !list_empty(&vslow_work_queue)) &&
-            atomic_read(&slow_work_thread_count) < slow_work_max_threads &&
-            !slow_work_may_not_start_new_thread)
-                slow_work_enqueue(&slow_work_new_thread);
-
-        /* find something to execute */
-        spin_lock_irq(&slow_work_queue_lock);
-        if (!list_empty(&vslow_work_queue) &&
-            atomic_read(&vslow_work_executing_count) < vsmax) {
-                work = list_entry(vslow_work_queue.next,
-                                  struct slow_work, link);
-                if (test_and_set_bit_lock(SLOW_WORK_EXECUTING, &work->flags))
-                        BUG();
-                list_del_init(&work->link);
-                atomic_inc(&vslow_work_executing_count);
-                very_slow = true;
-        } else if (!list_empty(&slow_work_queue)) {
-                work = list_entry(slow_work_queue.next,
-                                  struct slow_work, link);
-                if (test_and_set_bit_lock(SLOW_WORK_EXECUTING, &work->flags))
-                        BUG();
-                list_del_init(&work->link);
-                very_slow = false;
-        } else {
-                very_slow = false; /* avoid the compiler warning */
-        }
-
-        slow_work_set_thread_processing(id, work);
-        if (work) {
-                slow_work_mark_time(work);
-                slow_work_begin_exec(id, work);
-        }
-
-        spin_unlock_irq(&slow_work_queue_lock);
-
-        if (!work)
-                return false;
-
-        if (!test_and_clear_bit(SLOW_WORK_PENDING, &work->flags))
-                BUG();
-
-        /* don't execute if the work is in the process of being cancelled */
-        if (!test_bit(SLOW_WORK_CANCELLING, &work->flags))
-                work->ops->execute(work);
-
-        if (very_slow)
-                atomic_dec(&vslow_work_executing_count);
-        clear_bit_unlock(SLOW_WORK_EXECUTING, &work->flags);
-
-        /* wake up anyone waiting for this work to be complete */
-        wake_up_bit(&work->flags, SLOW_WORK_EXECUTING);
-
-        slow_work_end_exec(id, work);
-
-        /* if someone tried to enqueue the item whilst we were executing it,
-         * then it'll be left unenqueued to avoid multiple threads trying to
-         * execute it simultaneously
-         *
-         * there is, however, a race between us testing the pending flag and
-         * getting the spinlock, and between the enqueuer setting the pending
-         * flag and getting the spinlock, so we use a deferral bit to tell us
-         * if the enqueuer got there first
-         */
-        if (test_bit(SLOW_WORK_PENDING, &work->flags)) {
-                spin_lock_irq(&slow_work_queue_lock);
-
-                if (!test_bit(SLOW_WORK_EXECUTING, &work->flags) &&
-                    test_and_clear_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags))
-                        goto auto_requeue;
-
-                spin_unlock_irq(&slow_work_queue_lock);
-        }
-
-        /* sort out the race between module unloading and put_ref() */
-        slow_work_put_ref(work);
-        slow_work_done_thread_processing(id, work);
-
-        return true;
-
-auto_requeue:
-        /* we must complete the enqueue operation
-         * - we transfer our ref on the item back to the appropriate queue
-         * - don't wake another thread up as we're awake already
-         */
-        slow_work_mark_time(work);
-        if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags))
-                list_add_tail(&work->link, &vslow_work_queue);
-        else
-                list_add_tail(&work->link, &slow_work_queue);
-        spin_unlock_irq(&slow_work_queue_lock);
-        slow_work_clear_thread_processing(id);
-        return true;
-}
-
-/**
- * slow_work_sleep_till_thread_needed - Sleep till thread needed by other work
- * work: The work item under execution that wants to sleep
- * _timeout: Scheduler sleep timeout
- *
- * Allow a requeueable work item to sleep on a slow-work processor thread until
- * that thread is needed to do some other work or the sleep is interrupted by
- * some other event.
- *
- * The caller must set up a wake up event before calling this and must have set
- * the appropriate sleep mode (such as TASK_UNINTERRUPTIBLE) and tested its own
- * condition before calling this function as no test is made here.
- *
- * False is returned if there is nothing on the queue; true is returned if the
- * work item should be requeued
- */
-bool slow_work_sleep_till_thread_needed(struct slow_work *work,
-                                        signed long *_timeout)
-{
-        wait_queue_head_t *wfo_wq;
-        struct list_head *queue;
-
-        DEFINE_WAIT(wait);
-
-        if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
-                wfo_wq = &vslow_work_queue_waits_for_occupation;
-                queue = &vslow_work_queue;
-        } else {
-                wfo_wq = &slow_work_queue_waits_for_occupation;
-                queue = &slow_work_queue;
-        }
-
-        if (!list_empty(queue))
-                return true;
-
-        add_wait_queue_exclusive(wfo_wq, &wait);
-        if (list_empty(queue))
-                *_timeout = schedule_timeout(*_timeout);
-        finish_wait(wfo_wq, &wait);
-
-        return !list_empty(queue);
-}
-EXPORT_SYMBOL(slow_work_sleep_till_thread_needed);
-
-/**
- * slow_work_enqueue - Schedule a slow work item for processing
- * @work: The work item to queue
- *
- * Schedule a slow work item for processing.  If the item is already undergoing
- * execution, this guarantees not to re-enter the execution routine until the
- * first execution finishes.
- *
- * The item is pinned by this function as it retains a reference to it, managed
- * through the item operations.  The item is unpinned once it has been
- * executed.
- *
- * An item may hog the thread that is running it for a relatively large amount
- * of time, sufficient, for example, to perform several lookup, mkdir, create
- * and setxattr operations.  It may sleep on I/O and may sleep to obtain locks.
- *
- * Conversely, if a number of items are awaiting processing, it may take some
- * time before any given item is given attention.  The number of threads in the
- * pool may be increased to deal with demand, but only up to a limit.
- *
- * If SLOW_WORK_VERY_SLOW is set on the work item, then it will be placed in
- * the very slow queue, from which only a portion of the threads will be
- * allowed to pick items to execute.  This ensures that very slow items won't
- * overly block ones that are just ordinarily slow.
- *
- * Returns 0 if successful, -EAGAIN if not (or -ECANCELED if cancelled work is
- * attempted queued)
- */
-int slow_work_enqueue(struct slow_work *work)
-{
-        wait_queue_head_t *wfo_wq;
-        struct list_head *queue;
-        unsigned long flags;
-        int ret;
-
-        if (test_bit(SLOW_WORK_CANCELLING, &work->flags))
-                return -ECANCELED;
-
-        BUG_ON(slow_work_user_count <= 0);
-        BUG_ON(!work);
-        BUG_ON(!work->ops);
-
-        /* when honouring an enqueue request, we only promise that we will run
-         * the work function in the future; we do not promise to run it once
-         * per enqueue request
-         *
-         * we use the PENDING bit to merge together repeat requests without
-         * having to disable IRQs and take the spinlock, whilst still
-         * maintaining our promise
-         */
-        if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) {
-                if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
-                        wfo_wq = &vslow_work_queue_waits_for_occupation;
-                        queue = &vslow_work_queue;
-                } else {
-                        wfo_wq = &slow_work_queue_waits_for_occupation;
-                        queue = &slow_work_queue;
-                }
-
-                spin_lock_irqsave(&slow_work_queue_lock, flags);
-
-                if (unlikely(test_bit(SLOW_WORK_CANCELLING, &work->flags)))
-                        goto cancelled;
-
-                /* we promise that we will not attempt to execute the work
-                 * function in more than one thread simultaneously
-                 *
-                 * this, however, leaves us with a problem if we're asked to
-                 * enqueue the work whilst someone is executing the work
-                 * function as simply queueing the work immediately means that
-                 * another thread may try executing it whilst it is already
-                 * under execution
-                 *
-                 * to deal with this, we set the ENQ_DEFERRED bit instead of
-                 * enqueueing, and the thread currently executing the work
-                 * function will enqueue the work item when the work function
-                 * returns and it has cleared the EXECUTING bit
-                 */
-                if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) {
-                        set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags);
-                } else {
-                        ret = slow_work_get_ref(work);
-                        if (ret < 0)
-                                goto failed;
-                        slow_work_mark_time(work);
-                        list_add_tail(&work->link, queue);
-                        wake_up(&slow_work_thread_wq);
-
-                        /* if someone who could be requeued is sleeping on a
-                         * thread, then ask them to yield their thread */
-                        if (work->link.prev == queue)
-                                wake_up(wfo_wq);
-                }
-
-                spin_unlock_irqrestore(&slow_work_queue_lock, flags);
-        }
-        return 0;
-
-cancelled:
-        ret = -ECANCELED;
-failed:
-        spin_unlock_irqrestore(&slow_work_queue_lock, flags);
-        return ret;
-}
-EXPORT_SYMBOL(slow_work_enqueue);
-
-static int slow_work_wait(void *word)
-{
-        schedule();
-        return 0;
-}
-
-/**
- * slow_work_cancel - Cancel a slow work item
- * @work: The work item to cancel
- *
- * This function will cancel a previously enqueued work item. If we cannot
- * cancel the work item, it is guarenteed to have run when this function
- * returns.
- */
-void slow_work_cancel(struct slow_work *work)
-{
-        bool wait = true, put = false;
-
-        set_bit(SLOW_WORK_CANCELLING, &work->flags);
-        smp_mb();
-
-        /* if the work item is a delayed work item with an active timer, we
-         * need to wait for the timer to finish _before_ getting the spinlock,
-         * lest we deadlock against the timer routine
-         *
-         * the timer routine will leave DELAYED set if it notices the
-         * CANCELLING flag in time
-         */
-        if (test_bit(SLOW_WORK_DELAYED, &work->flags)) {
-                struct delayed_slow_work *dwork =
-                        container_of(work, struct delayed_slow_work, work);
-                del_timer_sync(&dwork->timer);
-        }
-
-        spin_lock_irq(&slow_work_queue_lock);
-
-        if (test_bit(SLOW_WORK_DELAYED, &work->flags)) {
-                /* the timer routine aborted or never happened, so we are left
-                 * holding the timer's reference on the item and should just
-                 * drop the pending flag and wait for any ongoing execution to
-                 * finish */
-                struct delayed_slow_work *dwork =
-                        container_of(work, struct delayed_slow_work, work);
-
-                BUG_ON(timer_pending(&dwork->timer));
-                BUG_ON(!list_empty(&work->link));
-
-                clear_bit(SLOW_WORK_DELAYED, &work->flags);
-                put = true;
-                clear_bit(SLOW_WORK_PENDING, &work->flags);
-
-        } else if (test_bit(SLOW_WORK_PENDING, &work->flags) &&
-                   !list_empty(&work->link)) {
-                /* the link in the pending queue holds a reference on the item
-                 * that we will need to release */
-                list_del_init(&work->link);
-                wait = false;
-                put = true;
-                clear_bit(SLOW_WORK_PENDING, &work->flags);
-
-        } else if (test_and_clear_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags)) {
-                /* the executor is holding our only reference on the item, so
-                 * we merely need to wait for it to finish executing */
-                clear_bit(SLOW_WORK_PENDING, &work->flags);
-        }
-
-        spin_unlock_irq(&slow_work_queue_lock);
-
-        /* the EXECUTING flag is set by the executor whilst the spinlock is set
-         * and before the item is dequeued - so assuming the above doesn't
-         * actually dequeue it, simply waiting for the EXECUTING flag to be
-         * released here should be sufficient */
-        if (wait)
-                wait_on_bit(&work->flags, SLOW_WORK_EXECUTING, slow_work_wait,
-                            TASK_UNINTERRUPTIBLE);
-
-        clear_bit(SLOW_WORK_CANCELLING, &work->flags);
-        if (put)
-                slow_work_put_ref(work);
-}
-EXPORT_SYMBOL(slow_work_cancel);
-
-/*
- * Handle expiry of the delay timer, indicating that a delayed slow work item
- * should now be queued if not cancelled
- */
-static void delayed_slow_work_timer(unsigned long data)
-{
-        wait_queue_head_t *wfo_wq;
-        struct list_head *queue;
-        struct slow_work *work = (struct slow_work *) data;
-        unsigned long flags;
-        bool queued = false, put = false, first = false;
-
-        if (test_bit(SLOW_WORK_VERY_SLOW, &work->flags)) {
-                wfo_wq = &vslow_work_queue_waits_for_occupation;
-                queue = &vslow_work_queue;
-        } else {
-                wfo_wq = &slow_work_queue_waits_for_occupation;
-                queue = &slow_work_queue;
-        }
-
-        spin_lock_irqsave(&slow_work_queue_lock, flags);
-        if (likely(!test_bit(SLOW_WORK_CANCELLING, &work->flags))) {
-                clear_bit(SLOW_WORK_DELAYED, &work->flags);
-
-                if (test_bit(SLOW_WORK_EXECUTING, &work->flags)) {
-                        /* we discard the reference the timer was holding in
-                         * favour of the one the executor holds */
-                        set_bit(SLOW_WORK_ENQ_DEFERRED, &work->flags);
-                        put = true;
-                } else {
-                        slow_work_mark_time(work);
-                        list_add_tail(&work->link, queue);
-                        queued = true;
-                        if (work->link.prev == queue)
-                                first = true;
-                }
-        }
-
-        spin_unlock_irqrestore(&slow_work_queue_lock, flags);
-        if (put)
-                slow_work_put_ref(work);
-        if (first)
-                wake_up(wfo_wq);
-        if (queued)
-                wake_up(&slow_work_thread_wq);
-}
-
-/**
- * delayed_slow_work_enqueue - Schedule a delayed slow work item for processing
- * @dwork: The delayed work item to queue
- * @delay: When to start executing the work, in jiffies from now
- *
- * This is similar to slow_work_enqueue(), but it adds a delay before the work
- * is actually queued for processing.
- *
- * The item can have delayed processing requested on it whilst it is being
- * executed.  The delay will begin immediately, and if it expires before the
- * item finishes executing, the item will be placed back on the queue when it
- * has done executing.
- */
-int delayed_slow_work_enqueue(struct delayed_slow_work *dwork,
-                              unsigned long delay)
-{
-        struct slow_work *work = &dwork->work;
-        unsigned long flags;
-        int ret;
-
-        if (delay == 0)
-                return slow_work_enqueue(&dwork->work);
-
-        BUG_ON(slow_work_user_count <= 0);
-        BUG_ON(!work);
-        BUG_ON(!work->ops);
-
-        if (test_bit(SLOW_WORK_CANCELLING, &work->flags))
-                return -ECANCELED;
-
-        if (!test_and_set_bit_lock(SLOW_WORK_PENDING, &work->flags)) {
-                spin_lock_irqsave(&slow_work_queue_lock, flags);
-
-                if (test_bit(SLOW_WORK_CANCELLING, &work->flags))
-                        goto cancelled;
-
-                /* the timer holds a reference whilst it is pending */
-                ret = slow_work_get_ref(work);
-                if (ret < 0)
-                        goto cant_get_ref;
-
-                if (test_and_set_bit(SLOW_WORK_DELAYED, &work->flags))
-                        BUG();
-                dwork->timer.expires = jiffies + delay;
-                dwork->timer.data = (unsigned long) work;
-                dwork->timer.function = delayed_slow_work_timer;
-                add_timer(&dwork->timer);
-
-                spin_unlock_irqrestore(&slow_work_queue_lock, flags);
-        }
-
-        return 0;
-
-cancelled:
-        ret = -ECANCELED;
-cant_get_ref:
-        spin_unlock_irqrestore(&slow_work_queue_lock, flags);
-        return ret;
-}
-EXPORT_SYMBOL(delayed_slow_work_enqueue);
-
-/*
- * Schedule a cull of the thread pool at some time in the near future
- */
-static void slow_work_schedule_cull(void)
-{
-        mod_timer(&slow_work_cull_timer,
-                  round_jiffies(jiffies + SLOW_WORK_CULL_TIMEOUT));
-}
-
-/*
- * Worker thread culling algorithm
- */
-static bool slow_work_cull_thread(void)
-{
-        unsigned long flags;
-        bool do_cull = false;
-
-        spin_lock_irqsave(&slow_work_queue_lock, flags);
-
-        if (slow_work_cull) {
-                slow_work_cull = false;
-
-                if (list_empty(&slow_work_queue) &&
-                    list_empty(&vslow_work_queue) &&
-                    atomic_read(&slow_work_thread_count) >
-                    slow_work_min_threads) {
-                        slow_work_schedule_cull();
-                        do_cull = true;
-                }
-        }
-
-        spin_unlock_irqrestore(&slow_work_queue_lock, flags);
-        return do_cull;
-}
-
-/*
- * Determine if there is slow work available for dispatch
- */
-static inline bool slow_work_available(int vsmax)
-{
-        return !list_empty(&slow_work_queue) ||
-                (!list_empty(&vslow_work_queue) &&
-                 atomic_read(&vslow_work_executing_count) < vsmax);
-}
-
-/*
- * Worker thread dispatcher
- */
-static int slow_work_thread(void *_data)
-{
-        int vsmax, id;
-
-        DEFINE_WAIT(wait);
-
-        set_freezable();
-        set_user_nice(current, -5);
-
-        /* allocate ourselves an ID */
-        spin_lock_irq(&slow_work_queue_lock);
-        id = find_first_zero_bit(slow_work_ids, SLOW_WORK_THREAD_LIMIT);
-        BUG_ON(id < 0 || id >= SLOW_WORK_THREAD_LIMIT);
-        __set_bit(id, slow_work_ids);
-        slow_work_set_thread_pid(id, current->pid);
-        spin_unlock_irq(&slow_work_queue_lock);
-
-        sprintf(current->comm, "kslowd%03u", id);
-
-        for (;;) {
-                vsmax = vslow_work_proportion;
-                vsmax *= atomic_read(&slow_work_thread_count);
-                vsmax /= 100;
-
-                prepare_to_wait_exclusive(&slow_work_thread_wq, &wait,
-                                          TASK_INTERRUPTIBLE);
-                if (!freezing(current) &&
-                    !slow_work_threads_should_exit &&
-                    !slow_work_available(vsmax) &&
-                    !slow_work_cull)
-                        schedule();
-                finish_wait(&slow_work_thread_wq, &wait);
-
-                try_to_freeze();
-
-                vsmax = vslow_work_proportion;
-                vsmax *= atomic_read(&slow_work_thread_count);
-                vsmax /= 100;
-
-                if (slow_work_available(vsmax) && slow_work_execute(id)) {
-                        cond_resched();
-                        if (list_empty(&slow_work_queue) &&
-                            list_empty(&vslow_work_queue) &&
-                            atomic_read(&slow_work_thread_count) >
-                            slow_work_min_threads)
-                                slow_work_schedule_cull();
-                        continue;
-                }
-
-                if (slow_work_threads_should_exit)
-                        break;
-
-                if (slow_work_cull && slow_work_cull_thread())
-                        break;
-        }
-
-        spin_lock_irq(&slow_work_queue_lock);
-        slow_work_set_thread_pid(id, 0);
-        __clear_bit(id, slow_work_ids);
-        spin_unlock_irq(&slow_work_queue_lock);
-
-        if (atomic_dec_and_test(&slow_work_thread_count))
-                complete_and_exit(&slow_work_last_thread_exited, 0);
-        return 0;
-}
-
-/*
- * Handle thread cull timer expiration
- */
-static void slow_work_cull_timeout(unsigned long data)
-{
-        slow_work_cull = true;
-        wake_up(&slow_work_thread_wq);
-}
-
-/*
- * Start a new slow work thread
- */
-static void slow_work_new_thread_execute(struct slow_work *work)
-{
-        struct task_struct *p;
-
-        if (slow_work_threads_should_exit)
-                return;
-
-        if (atomic_read(&slow_work_thread_count) >= slow_work_max_threads)
-                return;
-
-        if (!mutex_trylock(&slow_work_user_lock))
-                return;
-
-        slow_work_may_not_start_new_thread = true;
-        atomic_inc(&slow_work_thread_count);
-        p = kthread_run(slow_work_thread, NULL, "kslowd");
-        if (IS_ERR(p)) {
-                printk(KERN_DEBUG "Slow work thread pool: OOM\n");
-                if (atomic_dec_and_test(&slow_work_thread_count))
-                        BUG(); /* we're running on a slow work thread... */
-                mod_timer(&slow_work_oom_timer,
-                          round_jiffies(jiffies + SLOW_WORK_OOM_TIMEOUT));
-        } else {
-                /* ratelimit the starting of new threads */
-                mod_timer(&slow_work_oom_timer, jiffies + 1);
-        }
-
-        mutex_unlock(&slow_work_user_lock);
-}
-
-static const struct slow_work_ops slow_work_new_thread_ops = {
-        .owner          = THIS_MODULE,
-        .execute        = slow_work_new_thread_execute,
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        .desc           = slow_work_new_thread_desc,
-#endif
-};
-
-/*
- * post-OOM new thread start suppression expiration
- */
-static void slow_work_oom_timeout(unsigned long data)
-{
-        slow_work_may_not_start_new_thread = false;
-}
-
-#ifdef CONFIG_SYSCTL
-/*
- * Handle adjustment of the minimum number of threads
- */
-static int slow_work_min_threads_sysctl(struct ctl_table *table, int write,
-                                        void __user *buffer,
-                                        size_t *lenp, loff_t *ppos)
-{
-        int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-        int n;
-
-        if (ret == 0) {
-                mutex_lock(&slow_work_user_lock);
-                if (slow_work_user_count > 0) {
-                        /* see if we need to start or stop threads */
-                        n = atomic_read(&slow_work_thread_count) -
-                                slow_work_min_threads;
-
-                        if (n < 0 && !slow_work_may_not_start_new_thread)
-                                slow_work_enqueue(&slow_work_new_thread);
-                        else if (n > 0)
-                                slow_work_schedule_cull();
-                }
-                mutex_unlock(&slow_work_user_lock);
-        }
-
-        return ret;
-}
-
-/*
- * Handle adjustment of the maximum number of threads
- */
-static int slow_work_max_threads_sysctl(struct ctl_table *table, int write,
-                                        void __user *buffer,
-                                        size_t *lenp, loff_t *ppos)
-{
-        int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-        int n;
-
-        if (ret == 0) {
-                mutex_lock(&slow_work_user_lock);
-                if (slow_work_user_count > 0) {
-                        /* see if we need to stop threads */
-                        n = slow_work_max_threads -
-                                atomic_read(&slow_work_thread_count);
-
-                        if (n < 0)
-                                slow_work_schedule_cull();
-                }
-                mutex_unlock(&slow_work_user_lock);
-        }
-
-        return ret;
-}
-#endif /* CONFIG_SYSCTL */
-
-/**
- * slow_work_register_user - Register a user of the facility
- * @module: The module about to make use of the facility
- *
- * Register a user of the facility, starting up the initial threads if there
- * aren't any other users at this point.  This will return 0 if successful, or
- * an error if not.
- */
-int slow_work_register_user(struct module *module)
-{
-        struct task_struct *p;
-        int loop;
-
-        mutex_lock(&slow_work_user_lock);
-
-        if (slow_work_user_count == 0) {
-                printk(KERN_NOTICE "Slow work thread pool: Starting up\n");
-                init_completion(&slow_work_last_thread_exited);
-
-                slow_work_threads_should_exit = false;
-                slow_work_init(&slow_work_new_thread,
-                               &slow_work_new_thread_ops);
-                slow_work_may_not_start_new_thread = false;
-                slow_work_cull = false;
-
-                /* start the minimum number of threads */
-                for (loop = 0; loop < slow_work_min_threads; loop++) {
-                        atomic_inc(&slow_work_thread_count);
-                        p = kthread_run(slow_work_thread, NULL, "kslowd");
-                        if (IS_ERR(p))
-                                goto error;
-                }
-                printk(KERN_NOTICE "Slow work thread pool: Ready\n");
-        }
-
-        slow_work_user_count++;
-        mutex_unlock(&slow_work_user_lock);
-        return 0;
-
-error:
-        if (atomic_dec_and_test(&slow_work_thread_count))
-                complete(&slow_work_last_thread_exited);
-        if (loop > 0) {
-                printk(KERN_ERR "Slow work thread pool:"
-                       " Aborting startup on ENOMEM\n");
-                slow_work_threads_should_exit = true;
-                wake_up_all(&slow_work_thread_wq);
-                wait_for_completion(&slow_work_last_thread_exited);
-                printk(KERN_ERR "Slow work thread pool: Aborted\n");
-        }
-        mutex_unlock(&slow_work_user_lock);
-        return PTR_ERR(p);
-}
-EXPORT_SYMBOL(slow_work_register_user);
-
-/*
- * wait for all outstanding items from the calling module to complete
- * - note that more items may be queued whilst we're waiting
- */
-static void slow_work_wait_for_items(struct module *module)
-{
-#ifdef CONFIG_MODULES
-        DECLARE_WAITQUEUE(myself, current);
-        struct slow_work *work;
-        int loop;
-
-        mutex_lock(&slow_work_unreg_sync_lock);
-        add_wait_queue(&slow_work_unreg_wq, &myself);
-
-        for (;;) {
-                spin_lock_irq(&slow_work_queue_lock);
-
-                /* first of all, we wait for the last queued item in each list
-                 * to be processed */
-                list_for_each_entry_reverse(work, &vslow_work_queue, link) {
-                        if (work->owner == module) {
-                                set_current_state(TASK_UNINTERRUPTIBLE);
-                                slow_work_unreg_work_item = work;
-                                goto do_wait;
-                        }
-                }
-                list_for_each_entry_reverse(work, &slow_work_queue, link) {
-                        if (work->owner == module) {
-                                set_current_state(TASK_UNINTERRUPTIBLE);
-                                slow_work_unreg_work_item = work;
-                                goto do_wait;
-                        }
-                }
-
-                /* then we wait for the items being processed to finish */
-                slow_work_unreg_module = module;
-                smp_mb();
-                for (loop = 0; loop < SLOW_WORK_THREAD_LIMIT; loop++) {
-                        if (slow_work_thread_processing[loop] == module)
-                                goto do_wait;
-                }
-                spin_unlock_irq(&slow_work_queue_lock);
-                break; /* okay, we're done */
-
-        do_wait:
-                spin_unlock_irq(&slow_work_queue_lock);
-                schedule();
-                slow_work_unreg_work_item = NULL;
-                slow_work_unreg_module = NULL;
-        }
-
-        remove_wait_queue(&slow_work_unreg_wq, &myself);
-        mutex_unlock(&slow_work_unreg_sync_lock);
-#endif /* CONFIG_MODULES */
-}
-
-/**
- * slow_work_unregister_user - Unregister a user of the facility
- * @module: The module whose items should be cleared
- *
- * Unregister a user of the facility, killing all the threads if this was the
- * last one.
- *
- * This waits for all the work items belonging to the nominated module to go
- * away before proceeding.
- */
-void slow_work_unregister_user(struct module *module)
-{
-        /* first of all, wait for all outstanding items from the calling module
-         * to complete */
-        if (module)
-                slow_work_wait_for_items(module);
-
-        /* then we can actually go about shutting down the facility if need
-         * be */
-        mutex_lock(&slow_work_user_lock);
-
-        BUG_ON(slow_work_user_count <= 0);
-
-        slow_work_user_count--;
-        if (slow_work_user_count == 0) {
-                printk(KERN_NOTICE "Slow work thread pool: Shutting down\n");
-                slow_work_threads_should_exit = true;
-                del_timer_sync(&slow_work_cull_timer);
-                del_timer_sync(&slow_work_oom_timer);
-                wake_up_all(&slow_work_thread_wq);
-                wait_for_completion(&slow_work_last_thread_exited);
-                printk(KERN_NOTICE "Slow work thread pool:"
-                       " Shut down complete\n");
-        }
-
-        mutex_unlock(&slow_work_user_lock);
-}
-EXPORT_SYMBOL(slow_work_unregister_user);
-
-/*
- * Initialise the slow work facility
- */
-static int __init init_slow_work(void)
-{
-        unsigned nr_cpus = num_possible_cpus();
-
-        if (slow_work_max_threads < nr_cpus)
-                slow_work_max_threads = nr_cpus;
-#ifdef CONFIG_SYSCTL
-        if (slow_work_max_max_threads < nr_cpus * 2)
-                slow_work_max_max_threads = nr_cpus * 2;
-#endif
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        {
-                struct dentry *dbdir;
-
-                dbdir = debugfs_create_dir("slow_work", NULL);
-                if (dbdir && !IS_ERR(dbdir))
-                        debugfs_create_file("runqueue", S_IFREG | 0400, dbdir,
-                                            NULL, &slow_work_runqueue_fops);
-        }
-#endif
-        return 0;
-}
-
-subsys_initcall(init_slow_work);
diff --git a/kernel/slow-work.h b/kernel/slow-work.h
deleted file mode 100644
index a29ebd1ef41d..000000000000
--- a/kernel/slow-work.h
+++ /dev/null
@@ -1,72 +0,0 @@
-/* Slow work private definitions
- *
- * Copyright (C) 2009 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-
-#define SLOW_WORK_CULL_TIMEOUT (5 * HZ) /* cull threads 5s after running out of
-                                         * things to do */
-#define SLOW_WORK_OOM_TIMEOUT (5 * HZ)  /* can't start new threads for 5s after
-                                         * OOM */
-
-#define SLOW_WORK_THREAD_LIMIT  255     /* abs maximum number of slow-work threads */
-
-/*
- * slow-work.c
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-extern struct slow_work *slow_work_execs[];
-extern pid_t slow_work_pids[];
-extern rwlock_t slow_work_execs_lock;
-#endif
-
-extern struct list_head slow_work_queue;
-extern struct list_head vslow_work_queue;
-extern spinlock_t slow_work_queue_lock;
-
-/*
- * slow-work-debugfs.c
- */
-#ifdef CONFIG_SLOW_WORK_DEBUG
-extern const struct file_operations slow_work_runqueue_fops;
-
-extern void slow_work_new_thread_desc(struct slow_work *, struct seq_file *);
-#endif
-
-/*
- * Helper functions
- */
-static inline void slow_work_set_thread_pid(int id, pid_t pid)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        slow_work_pids[id] = pid;
-#endif
-}
-
-static inline void slow_work_mark_time(struct slow_work *work)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        work->mark = CURRENT_TIME;
-#endif
-}
-
-static inline void slow_work_begin_exec(int id, struct slow_work *work)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        slow_work_execs[id] = work;
-#endif
-}
-
-static inline void slow_work_end_exec(int id, struct slow_work *work)
-{
-#ifdef CONFIG_SLOW_WORK_DEBUG
-        write_lock(&slow_work_execs_lock);
-        slow_work_execs[id] = NULL;
-        write_unlock(&slow_work_execs_lock);
-#endif
-}
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9acfce0cdfdb..6d850bf0a517 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -50,7 +50,6 @@
 #include <linux/acpi.h>
 #include <linux/reboot.h>
 #include <linux/ftrace.h>
-#include <linux/slow-work.h>
 #include <linux/perf_event.h>
 #include <linux/kprobes.h>
 #include <linux/pipe_fs_i.h>
@@ -917,13 +916,6 @@ static struct ctl_table kern_table[] = {
                 .proc_handler   = proc_dointvec,
         },
 #endif
-#ifdef CONFIG_SLOW_WORK
-        {
-                .procname       = "slow-work",
-                .mode           = 0555,
-                .child          = slow_work_sysctls,
-        },
-#endif
 #ifdef CONFIG_PERF_EVENTS
         {
                 .procname       = "perf_event_paranoid",
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 6eb97bbdefb1..538501c6ea50 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -323,17 +323,6 @@ config STACK_TRACER
 
           Say N if unsure.
 
-config WORKQUEUE_TRACER
-        bool "Trace workqueues"
-        select GENERIC_TRACER
-        help
-          The workqueue tracer provides some statistical information
-          about each cpu workqueue thread such as the number of the
-          works inserted and executed since their creation. It can help
-          to evaluate the amount of work each of them has to perform.
-          For example it can help a developer to decide whether he should
-          choose a per-cpu workqueue instead of a singlethreaded one.
-
 config BLK_DEV_IO_TRACE
         bool "Support for tracing block IO actions"
         depends on SYSFS
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 59fef1531dd2..9ca34cddaf6d 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -33,41 +33,272 @@
 #include <linux/kallsyms.h>
 #include <linux/debug_locks.h>
 #include <linux/lockdep.h>
-#define CREATE_TRACE_POINTS
-#include <trace/events/workqueue.h>
+#include <linux/idr.h>
+
+#include "workqueue_sched.h"
+
+enum {
+        /* global_cwq flags */
+        GCWQ_MANAGE_WORKERS     = 1 << 0,       /* need to manage workers */
+        GCWQ_MANAGING_WORKERS   = 1 << 1,       /* managing workers */
+        GCWQ_DISASSOCIATED      = 1 << 2,       /* cpu can't serve workers */
+        GCWQ_FREEZING           = 1 << 3,       /* freeze in progress */
+        GCWQ_HIGHPRI_PENDING    = 1 << 4,       /* highpri works on queue */
+
+        /* worker flags */
+        WORKER_STARTED          = 1 << 0,       /* started */
+        WORKER_DIE              = 1 << 1,       /* die die die */
+        WORKER_IDLE             = 1 << 2,       /* is idle */
+        WORKER_PREP             = 1 << 3,       /* preparing to run works */
+        WORKER_ROGUE            = 1 << 4,       /* not bound to any cpu */
+        WORKER_REBIND           = 1 << 5,       /* mom is home, come back */
+        WORKER_CPU_INTENSIVE    = 1 << 6,       /* cpu intensive */
+        WORKER_UNBOUND          = 1 << 7,       /* worker is unbound */
+
+        WORKER_NOT_RUNNING      = WORKER_PREP | WORKER_ROGUE | WORKER_REBIND |
+                                  WORKER_CPU_INTENSIVE | WORKER_UNBOUND,
+
+        /* gcwq->trustee_state */
+        TRUSTEE_START           = 0,            /* start */
+        TRUSTEE_IN_CHARGE       = 1,            /* trustee in charge of gcwq */
+        TRUSTEE_BUTCHER         = 2,            /* butcher workers */
+        TRUSTEE_RELEASE         = 3,            /* release workers */
+        TRUSTEE_DONE            = 4,            /* trustee is done */
+
+        BUSY_WORKER_HASH_ORDER  = 6,            /* 64 pointers */
+        BUSY_WORKER_HASH_SIZE   = 1 << BUSY_WORKER_HASH_ORDER,
+        BUSY_WORKER_HASH_MASK   = BUSY_WORKER_HASH_SIZE - 1,
+
+        MAX_IDLE_WORKERS_RATIO  = 4,            /* 1/4 of busy can be idle */
+        IDLE_WORKER_TIMEOUT     = 300 * HZ,     /* keep idle ones for 5 mins */
+
+        MAYDAY_INITIAL_TIMEOUT  = HZ / 100,     /* call for help after 10ms */
+        MAYDAY_INTERVAL         = HZ / 10,      /* and then every 100ms */
+        CREATE_COOLDOWN         = HZ,           /* time to breath after fail */
+        TRUSTEE_COOLDOWN        = HZ / 10,      /* for trustee draining */
+
+        /*
+         * Rescue workers are used only on emergencies and shared by
+         * all cpus.  Give -20.
+         */
+        RESCUER_NICE_LEVEL      = -20,
+};
 
 /*
- * The per-CPU workqueue (if single thread, we always use the first
- * possible cpu).
+ * Structure fields follow one of the following exclusion rules.
+ *
+ * I: Set during initialization and read-only afterwards.
+ *
+ * P: Preemption protected.  Disabling preemption is enough and should
+ *    only be modified and accessed from the local cpu.
+ *
+ * L: gcwq->lock protected.  Access with gcwq->lock held.
+ *
+ * X: During normal operation, modification requires gcwq->lock and
+ *    should be done only from local cpu.  Either disabling preemption
+ *    on local cpu or grabbing gcwq->lock is enough for read access.
+ *    If GCWQ_DISASSOCIATED is set, it's identical to L.
+ *
+ * F: wq->flush_mutex protected.
+ *
+ * W: workqueue_lock protected.
  */
-struct cpu_workqueue_struct {
 
-        spinlock_t lock;
+struct global_cwq;
 
-        struct list_head worklist;
-        wait_queue_head_t more_work;
-        struct work_struct *current_work;
+/*
+ * The poor guys doing the actual heavy lifting.  All on-duty workers
+ * are either serving the manager role, on idle list or on busy hash.
+ */
+struct worker {
+        /* on idle list while idle, on busy hash table while busy */
+        union {
+                struct list_head        entry;  /* L: while idle */
+                struct hlist_node       hentry; /* L: while busy */
+        };
 
-        struct workqueue_struct *wq;
-        struct task_struct *thread;
-} ____cacheline_aligned;
+        struct work_struct      *current_work;  /* L: work being processed */
+        struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */
+        struct list_head        scheduled;      /* L: scheduled works */
+        struct task_struct      *task;          /* I: worker task */
+        struct global_cwq       *gcwq;          /* I: the associated gcwq */
+        /* 64 bytes boundary on 64bit, 32 on 32bit */
+        unsigned long           last_active;    /* L: last active timestamp */
+        unsigned int            flags;          /* X: flags */
+        int                     id;             /* I: worker id */
+        struct work_struct      rebind_work;    /* L: rebind worker to cpu */
+};
+
+/*
+ * Global per-cpu workqueue.  There's one and only one for each cpu
+ * and all works are queued and processed here regardless of their
+ * target workqueues.
+ */
+struct global_cwq {
+        spinlock_t              lock;           /* the gcwq lock */
+        struct list_head        worklist;       /* L: list of pending works */
+        unsigned int            cpu;            /* I: the associated cpu */
+        unsigned int            flags;          /* L: GCWQ_* flags */
+
+        int                     nr_workers;     /* L: total number of workers */
+        int                     nr_idle;        /* L: currently idle ones */
+
+        /* workers are chained either in the idle_list or busy_hash */
+        struct list_head        idle_list;      /* X: list of idle workers */
+        struct hlist_head       busy_hash[BUSY_WORKER_HASH_SIZE];
+                                                /* L: hash of busy workers */
+
+        struct timer_list       idle_timer;     /* L: worker idle timeout */
+        struct timer_list       mayday_timer;   /* L: SOS timer for dworkers */
+
+        struct ida              worker_ida;     /* L: for worker IDs */
+
+        struct task_struct      *trustee;       /* L: for gcwq shutdown */
+        unsigned int            trustee_state;  /* L: trustee state */
+        wait_queue_head_t       trustee_wait;   /* trustee wait */
+        struct worker           *first_idle;    /* L: first idle worker */
+} ____cacheline_aligned_in_smp;
+
+/*
+ * The per-CPU workqueue.  The lower WORK_STRUCT_FLAG_BITS of
+ * work_struct->data are used for flags and thus cwqs need to be
+ * aligned at two's power of the number of flag bits.
+ */
+struct cpu_workqueue_struct {
+        struct global_cwq       *gcwq;          /* I: the associated gcwq */
+        struct workqueue_struct *wq;            /* I: the owning workqueue */
+        int                     work_color;     /* L: current color */
+        int                     flush_color;    /* L: flushing color */
+        int                     nr_in_flight[WORK_NR_COLORS];
+                                                /* L: nr of in_flight works */
+        int                     nr_active;      /* L: nr of active works */
+        int                     max_active;     /* L: max active works */
+        struct list_head        delayed_works;  /* L: delayed works */
+};
+
+/*
+ * Structure used to wait for workqueue flush.
+ */
+struct wq_flusher {
+        struct list_head        list;           /* F: list of flushers */
+        int                     flush_color;    /* F: flush color waiting for */
+        struct completion       done;           /* flush completion */
+};
+
+/*
+ * All cpumasks are assumed to be always set on UP and thus can't be
+ * used to determine whether there's something to be done.
+ */
+#ifdef CONFIG_SMP
+typedef cpumask_var_t mayday_mask_t;
+#define mayday_test_and_set_cpu(cpu, mask)      \
+        cpumask_test_and_set_cpu((cpu), (mask))
+#define mayday_clear_cpu(cpu, mask)             cpumask_clear_cpu((cpu), (mask))
+#define for_each_mayday_cpu(cpu, mask)          for_each_cpu((cpu), (mask))
+#define alloc_mayday_mask(maskp, gfp)           alloc_cpumask_var((maskp), (gfp))
+#define free_mayday_mask(mask)                  free_cpumask_var((mask))
+#else
+typedef unsigned long mayday_mask_t;
+#define mayday_test_and_set_cpu(cpu, mask)      test_and_set_bit(0, &(mask))
+#define mayday_clear_cpu(cpu, mask)             clear_bit(0, &(mask))
+#define for_each_mayday_cpu(cpu, mask)          if ((cpu) = 0, (mask))
+#define alloc_mayday_mask(maskp, gfp)           true
+#define free_mayday_mask(mask)                  do { } while (0)
+#endif
 
 /*
  * The externally visible workqueue abstraction is an array of
  * per-CPU workqueues:
  */
 struct workqueue_struct {
-        struct cpu_workqueue_struct *cpu_wq;
-        struct list_head list;
-        const char *name;
-        int singlethread;
-        int freezeable;         /* Freeze threads during suspend */
-        int rt;
+        unsigned int            flags;          /* I: WQ_* flags */
+        union {
+                struct cpu_workqueue_struct __percpu    *pcpu;
+                struct cpu_workqueue_struct             *single;
+                unsigned long                           v;
+        } cpu_wq;                               /* I: cwq's */
+        struct list_head        list;           /* W: list of all workqueues */
+
+        struct mutex            flush_mutex;    /* protects wq flushing */
+        int                     work_color;     /* F: current work color */
+        int                     flush_color;    /* F: current flush color */
+        atomic_t                nr_cwqs_to_flush; /* flush in progress */
+        struct wq_flusher       *first_flusher; /* F: first flusher */
+        struct list_head        flusher_queue;  /* F: flush waiters */
+        struct list_head        flusher_overflow; /* F: flush overflow list */
+
+        mayday_mask_t           mayday_mask;    /* cpus requesting rescue */
+        struct worker           *rescuer;       /* I: rescue worker */
+
+        int                     saved_max_active; /* W: saved cwq max_active */
+        const char              *name;          /* I: workqueue name */
 #ifdef CONFIG_LOCKDEP
-        struct lockdep_map lockdep_map;
+        struct lockdep_map      lockdep_map;
 #endif
 };
 
+struct workqueue_struct *system_wq __read_mostly;
+struct workqueue_struct *system_long_wq __read_mostly;
+struct workqueue_struct *system_nrt_wq __read_mostly;
+struct workqueue_struct *system_unbound_wq __read_mostly;
+EXPORT_SYMBOL_GPL(system_wq);
+EXPORT_SYMBOL_GPL(system_long_wq);
+EXPORT_SYMBOL_GPL(system_nrt_wq);
+EXPORT_SYMBOL_GPL(system_unbound_wq);
+
+#define for_each_busy_worker(worker, i, pos, gcwq)                      \
+        for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)                     \
+                hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry)
+
+static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask,
+                                  unsigned int sw)
+{
+        if (cpu < nr_cpu_ids) {
+                if (sw & 1) {
+                        cpu = cpumask_next(cpu, mask);
+                        if (cpu < nr_cpu_ids)
+                                return cpu;
+                }
+                if (sw & 2)
+                        return WORK_CPU_UNBOUND;
+        }
+        return WORK_CPU_NONE;
+}
+
+static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
+                                struct workqueue_struct *wq)
+{
+        return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2);
+}
+
+/*
+ * CPU iterators
+ *
+ * An extra gcwq is defined for an invalid cpu number
+ * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any
+ * specific CPU.  The following iterators are similar to
+ * for_each_*_cpu() iterators but also considers the unbound gcwq.
+ *
+ * for_each_gcwq_cpu()          : possible CPUs + WORK_CPU_UNBOUND
+ * for_each_online_gcwq_cpu()   : online CPUs + WORK_CPU_UNBOUND
+ * for_each_cwq_cpu()           : possible CPUs for bound workqueues,
+ *                                WORK_CPU_UNBOUND for unbound workqueues
+ */
+#define for_each_gcwq_cpu(cpu)                                          \
+        for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3);         \
+             (cpu) < WORK_CPU_NONE;                                     \
+             (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3))
+
+#define for_each_online_gcwq_cpu(cpu)                                   \
+        for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3);           \
+             (cpu) < WORK_CPU_NONE;                                     \
+             (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3))
+
+#define for_each_cwq_cpu(cpu, wq)                                       \
+        for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq));        \
+             (cpu) < WORK_CPU_NONE;                                     \
+             (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq)))
+
 #ifdef CONFIG_LOCKDEP
 /**
  * in_workqueue_context() - in context of specified workqueue?
@@ -122,7 +353,7 @@ static int work_fixup_activate(void *addr, enum debug_obj_state state)
                  * statically initialized. We just make sure that it
                  * is tracked in the object tracker.
                  */
-                if (test_bit(WORK_STRUCT_STATIC, work_data_bits(work))) {
+                if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) {
                         debug_object_init(work, &work_debug_descr);
                         debug_object_activate(work, &work_debug_descr);
                         return 0;
@@ -196,94 +427,575 @@ static inline void debug_work_deactivate(struct work_struct *work) { }
 /* Serializes the accesses to the list of workqueues. */
 static DEFINE_SPINLOCK(workqueue_lock);
 static LIST_HEAD(workqueues);
+static bool workqueue_freezing;         /* W: have wqs started freezing? */
+
+/*
+ * The almighty global cpu workqueues.  nr_running is the only field
+ * which is expected to be used frequently by other cpus via
+ * try_to_wake_up().  Put it in a separate cacheline.
+ */
+static DEFINE_PER_CPU(struct global_cwq, global_cwq);
+static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, gcwq_nr_running);
+
+/*
+ * Global cpu workqueue and nr_running counter for unbound gcwq.  The
+ * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its
+ * workers have WORKER_UNBOUND set.
+ */
+static struct global_cwq unbound_global_cwq;
+static atomic_t unbound_gcwq_nr_running = ATOMIC_INIT(0);       /* always 0 */
+
+static int worker_thread(void *__worker);
+
+static struct global_cwq *get_gcwq(unsigned int cpu)
+{
+        if (cpu != WORK_CPU_UNBOUND)
+                return &per_cpu(global_cwq, cpu);
+        else
+                return &unbound_global_cwq;
+}
+
+static atomic_t *get_gcwq_nr_running(unsigned int cpu)
+{
+        if (cpu != WORK_CPU_UNBOUND)
+                return &per_cpu(gcwq_nr_running, cpu);
+        else
+                return &unbound_gcwq_nr_running;
+}
+
+static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
+                                            struct workqueue_struct *wq)
+{
+        if (!(wq->flags & WQ_UNBOUND)) {
+                if (likely(cpu < nr_cpu_ids)) {
+#ifdef CONFIG_SMP
+                        return per_cpu_ptr(wq->cpu_wq.pcpu, cpu);
+#else
+                        return wq->cpu_wq.single;
+#endif
+                }
+        } else if (likely(cpu == WORK_CPU_UNBOUND))
+                return wq->cpu_wq.single;
+        return NULL;
+}
+
+static unsigned int work_color_to_flags(int color)
+{
+        return color << WORK_STRUCT_COLOR_SHIFT;
+}
+
+static int get_work_color(struct work_struct *work)
+{
+        return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) &
+                ((1 << WORK_STRUCT_COLOR_BITS) - 1);
+}
+
+static int work_next_color(int color)
+{
+        return (color + 1) % WORK_NR_COLORS;
+}
 
-static int singlethread_cpu __read_mostly;
-static const struct cpumask *cpu_singlethread_map __read_mostly;
 /*
- * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD
- * flushes cwq->worklist. This means that flush_workqueue/wait_on_work
- * which comes in between can't use for_each_online_cpu(). We could
- * use cpu_possible_map, the cpumask below is more a documentation
- * than optimization.
+ * A work's data points to the cwq with WORK_STRUCT_CWQ set while the
+ * work is on queue.  Once execution starts, WORK_STRUCT_CWQ is
+ * cleared and the work data contains the cpu number it was last on.
+ *
+ * set_work_{cwq|cpu}() and clear_work_data() can be used to set the
+ * cwq, cpu or clear work->data.  These functions should only be
+ * called while the work is owned - ie. while the PENDING bit is set.
+ *
+ * get_work_[g]cwq() can be used to obtain the gcwq or cwq
+ * corresponding to a work.  gcwq is available once the work has been
+ * queued anywhere after initialization.  cwq is available only from
+ * queueing until execution starts.
  */
-static cpumask_var_t cpu_populated_map __read_mostly;
+static inline void set_work_data(struct work_struct *work, unsigned long data,
+                                 unsigned long flags)
+{
+        BUG_ON(!work_pending(work));
+        atomic_long_set(&work->data, data | flags | work_static(work));
+}
 
-/* If it's single threaded, it isn't in the list of workqueues. */
-static inline int is_wq_single_threaded(struct workqueue_struct *wq)
+static void set_work_cwq(struct work_struct *work,
+                         struct cpu_workqueue_struct *cwq,
+                         unsigned long extra_flags)
 {
-        return wq->singlethread;
+        set_work_data(work, (unsigned long)cwq,
+                      WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags);
 }
 
-static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq)
+static void set_work_cpu(struct work_struct *work, unsigned int cpu)
 {
-        return is_wq_single_threaded(wq)
-                ? cpu_singlethread_map : cpu_populated_map;
+        set_work_data(work, cpu << WORK_STRUCT_FLAG_BITS, WORK_STRUCT_PENDING);
 }
 
-static
-struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu)
+static void clear_work_data(struct work_struct *work)
 {
-        if (unlikely(is_wq_single_threaded(wq)))
-                cpu = singlethread_cpu;
-        return per_cpu_ptr(wq->cpu_wq, cpu);
+        set_work_data(work, WORK_STRUCT_NO_CPU, 0);
+}
+
+static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work)
+{
+        unsigned long data = atomic_long_read(&work->data);
+
+        if (data & WORK_STRUCT_CWQ)
+                return (void *)(data & WORK_STRUCT_WQ_DATA_MASK);
+        else
+                return NULL;
+}
+
+static struct global_cwq *get_work_gcwq(struct work_struct *work)
+{
+        unsigned long data = atomic_long_read(&work->data);
+        unsigned int cpu;
+
+        if (data & WORK_STRUCT_CWQ)
+                return ((struct cpu_workqueue_struct *)
+                        (data & WORK_STRUCT_WQ_DATA_MASK))->gcwq;
+
+        cpu = data >> WORK_STRUCT_FLAG_BITS;
+        if (cpu == WORK_CPU_NONE)
+                return NULL;
+
+        BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND);
+        return get_gcwq(cpu);
 }
 
 /*
- * Set the workqueue on which a work item is to be run
- * - Must *only* be called if the pending flag is set
+ * Policy functions.  These define the policies on how the global
+ * worker pool is managed.  Unless noted otherwise, these functions
+ * assume that they're being called with gcwq->lock held.
  */
-static inline void set_wq_data(struct work_struct *work,
-                                struct cpu_workqueue_struct *cwq)
+
+static bool __need_more_worker(struct global_cwq *gcwq)
 {
-        unsigned long new;
+        return !atomic_read(get_gcwq_nr_running(gcwq->cpu)) ||
+                gcwq->flags & GCWQ_HIGHPRI_PENDING;
+}
 
-        BUG_ON(!work_pending(work));
+/*
+ * Need to wake up a worker?  Called from anything but currently
+ * running workers.
+ */
+static bool need_more_worker(struct global_cwq *gcwq)
+{
+        return !list_empty(&gcwq->worklist) && __need_more_worker(gcwq);
+}
+
+/* Can I start working?  Called from busy but !running workers. */
+static bool may_start_working(struct global_cwq *gcwq)
+{
+        return gcwq->nr_idle;
+}
+
+/* Do I need to keep working?  Called from currently running workers. */
+static bool keep_working(struct global_cwq *gcwq)
+{
+        atomic_t *nr_running = get_gcwq_nr_running(gcwq->cpu);
+
+        return !list_empty(&gcwq->worklist) && atomic_read(nr_running) <= 1;
+}
+
+/* Do we need a new worker?  Called from manager. */
+static bool need_to_create_worker(struct global_cwq *gcwq)
+{
+        return need_more_worker(gcwq) && !may_start_working(gcwq);
+}
 
-        new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING);
-        new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work);
-        atomic_long_set(&work->data, new);
+/* Do I need to be the manager? */
+static bool need_to_manage_workers(struct global_cwq *gcwq)
+{
+        return need_to_create_worker(gcwq) || gcwq->flags & GCWQ_MANAGE_WORKERS;
+}
+
+/* Do we have too many workers and should some go away? */
+static bool too_many_workers(struct global_cwq *gcwq)
+{
+        bool managing = gcwq->flags & GCWQ_MANAGING_WORKERS;
+        int nr_idle = gcwq->nr_idle + managing; /* manager is considered idle */
+        int nr_busy = gcwq->nr_workers - nr_idle;
+
+        return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
 }
 
 /*
- * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued.
+ * Wake up functions.
+ */
+
+/* Return the first worker.  Safe with preemption disabled */
+static struct worker *first_worker(struct global_cwq *gcwq)
+{
+        if (unlikely(list_empty(&gcwq->idle_list)))
+                return NULL;
+
+        return list_first_entry(&gcwq->idle_list, struct worker, entry);
+}
+
+/**
+ * wake_up_worker - wake up an idle worker
+ * @gcwq: gcwq to wake worker for
+ *
+ * Wake up the first idle worker of @gcwq.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void wake_up_worker(struct global_cwq *gcwq)
+{
+        struct worker *worker = first_worker(gcwq);
+
+        if (likely(worker))
+                wake_up_process(worker->task);
+}
+
+/**
+ * wq_worker_waking_up - a worker is waking up
+ * @task: task waking up
+ * @cpu: CPU @task is waking up to
+ *
+ * This function is called during try_to_wake_up() when a worker is
+ * being awoken.
+ *
+ * CONTEXT:
+ * spin_lock_irq(rq->lock)
+ */
+void wq_worker_waking_up(struct task_struct *task, unsigned int cpu)
+{
+        struct worker *worker = kthread_data(task);
+
+        if (likely(!(worker->flags & WORKER_NOT_RUNNING)))
+                atomic_inc(get_gcwq_nr_running(cpu));
+}
+
+/**
+ * wq_worker_sleeping - a worker is going to sleep
+ * @task: task going to sleep
+ * @cpu: CPU in question, must be the current CPU number
+ *
+ * This function is called during schedule() when a busy worker is
+ * going to sleep.  Worker on the same cpu can be woken up by
+ * returning pointer to its task.
+ *
+ * CONTEXT:
+ * spin_lock_irq(rq->lock)
+ *
+ * RETURNS:
+ * Worker task on @cpu to wake up, %NULL if none.
+ */
+struct task_struct *wq_worker_sleeping(struct task_struct *task,
+                                       unsigned int cpu)
+{
+        struct worker *worker = kthread_data(task), *to_wakeup = NULL;
+        struct global_cwq *gcwq = get_gcwq(cpu);
+        atomic_t *nr_running = get_gcwq_nr_running(cpu);
+
+        if (unlikely(worker->flags & WORKER_NOT_RUNNING))
+                return NULL;
+
+        /* this can only happen on the local cpu */
+        BUG_ON(cpu != raw_smp_processor_id());
+
+        /*
+         * The counterpart of the following dec_and_test, implied mb,
+         * worklist not empty test sequence is in insert_work().
+         * Please read comment there.
+         *
+         * NOT_RUNNING is clear.  This means that trustee is not in
+         * charge and we're running on the local cpu w/ rq lock held
+         * and preemption disabled, which in turn means that none else
+         * could be manipulating idle_list, so dereferencing idle_list
+         * without gcwq lock is safe.
+         */
+        if (atomic_dec_and_test(nr_running) && !list_empty(&gcwq->worklist))
+                to_wakeup = first_worker(gcwq);
+        return to_wakeup ? to_wakeup->task : NULL;
+}
+
+/**
+ * worker_set_flags - set worker flags and adjust nr_running accordingly
+ * @worker: self
+ * @flags: flags to set
+ * @wakeup: wakeup an idle worker if necessary
+ *
+ * Set @flags in @worker->flags and adjust nr_running accordingly.  If
+ * nr_running becomes zero and @wakeup is %true, an idle worker is
+ * woken up.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock)
+ */
+static inline void worker_set_flags(struct worker *worker, unsigned int flags,
+                                    bool wakeup)
+{
+        struct global_cwq *gcwq = worker->gcwq;
+
+        WARN_ON_ONCE(worker->task != current);
+
+        /*
+         * If transitioning into NOT_RUNNING, adjust nr_running and
+         * wake up an idle worker as necessary if requested by
+         * @wakeup.
+         */
+        if ((flags & WORKER_NOT_RUNNING) &&
+            !(worker->flags & WORKER_NOT_RUNNING)) {
+                atomic_t *nr_running = get_gcwq_nr_running(gcwq->cpu);
+
+                if (wakeup) {
+                        if (atomic_dec_and_test(nr_running) &&
+                            !list_empty(&gcwq->worklist))
+                                wake_up_worker(gcwq);
+                } else
+                        atomic_dec(nr_running);
+        }
+
+        worker->flags |= flags;
+}
+
+/**
+ * worker_clr_flags - clear worker flags and adjust nr_running accordingly
+ * @worker: self
+ * @flags: flags to clear
+ *
+ * Clear @flags in @worker->flags and adjust nr_running accordingly.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock)
+ */
+static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
+{
+        struct global_cwq *gcwq = worker->gcwq;
+        unsigned int oflags = worker->flags;
+
+        WARN_ON_ONCE(worker->task != current);
+
+        worker->flags &= ~flags;
+
+        /* if transitioning out of NOT_RUNNING, increment nr_running */
+        if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
+                if (!(worker->flags & WORKER_NOT_RUNNING))
+                        atomic_inc(get_gcwq_nr_running(gcwq->cpu));
+}
+
+/**
+ * busy_worker_head - return the busy hash head for a work
+ * @gcwq: gcwq of interest
+ * @work: work to be hashed
+ *
+ * Return hash head of @gcwq for @work.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to the hash head.
+ */
+static struct hlist_head *busy_worker_head(struct global_cwq *gcwq,
+                                           struct work_struct *work)
+{
+        const int base_shift = ilog2(sizeof(struct work_struct));
+        unsigned long v = (unsigned long)work;
+
+        /* simple shift and fold hash, do we need something better? */
+        v >>= base_shift;
+        v += v >> BUSY_WORKER_HASH_ORDER;
+        v &= BUSY_WORKER_HASH_MASK;
+
+        return &gcwq->busy_hash[v];
+}
+
+/**
+ * __find_worker_executing_work - find worker which is executing a work
+ * @gcwq: gcwq of interest
+ * @bwh: hash head as returned by busy_worker_head()
+ * @work: work to find worker for
+ *
+ * Find a worker which is executing @work on @gcwq.  @bwh should be
+ * the hash head obtained by calling busy_worker_head() with the same
+ * work.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to worker which is executing @work if found, NULL
+ * otherwise.
+ */
+static struct worker *__find_worker_executing_work(struct global_cwq *gcwq,
+                                                   struct hlist_head *bwh,
+                                                   struct work_struct *work)
+{
+        struct worker *worker;
+        struct hlist_node *tmp;
+
+        hlist_for_each_entry(worker, tmp, bwh, hentry)
+                if (worker->current_work == work)
+                        return worker;
+        return NULL;
+}
+
+/**
+ * find_worker_executing_work - find worker which is executing a work
+ * @gcwq: gcwq of interest
+ * @work: work to find worker for
+ *
+ * Find a worker which is executing @work on @gcwq.  This function is
+ * identical to __find_worker_executing_work() except that this
+ * function calculates @bwh itself.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to worker which is executing @work if found, NULL
+ * otherwise.
  */
-static inline void clear_wq_data(struct work_struct *work)
+static struct worker *find_worker_executing_work(struct global_cwq *gcwq,
+                                                 struct work_struct *work)
 {
-        unsigned long flags = *work_data_bits(work) &
-                                (1UL << WORK_STRUCT_STATIC);
-        atomic_long_set(&work->data, flags);
+        return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work),
+                                            work);
 }
 
-static inline
-struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
+/**
+ * gcwq_determine_ins_pos - find insertion position
+ * @gcwq: gcwq of interest
+ * @cwq: cwq a work is being queued for
+ *
+ * A work for @cwq is about to be queued on @gcwq, determine insertion
+ * position for the work.  If @cwq is for HIGHPRI wq, the work is
+ * queued at the head of the queue but in FIFO order with respect to
+ * other HIGHPRI works; otherwise, at the end of the queue.  This
+ * function also sets GCWQ_HIGHPRI_PENDING flag to hint @gcwq that
+ * there are HIGHPRI works pending.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ *
+ * RETURNS:
+ * Pointer to inserstion position.
+ */
+static inline struct list_head *gcwq_determine_ins_pos(struct global_cwq *gcwq,
+                                               struct cpu_workqueue_struct *cwq)
 {
-        return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK);
+        struct work_struct *twork;
+
+        if (likely(!(cwq->wq->flags & WQ_HIGHPRI)))
+                return &gcwq->worklist;
+
+        list_for_each_entry(twork, &gcwq->worklist, entry) {
+                struct cpu_workqueue_struct *tcwq = get_work_cwq(twork);
+
+                if (!(tcwq->wq->flags & WQ_HIGHPRI))
+                        break;
+        }
+
+        gcwq->flags |= GCWQ_HIGHPRI_PENDING;
+        return &twork->entry;
 }
 
+/**
+ * insert_work - insert a work into gcwq
+ * @cwq: cwq @work belongs to
+ * @work: work to insert
+ * @head: insertion point
+ * @extra_flags: extra WORK_STRUCT_* flags to set
+ *
+ * Insert @work which belongs to @cwq into @gcwq after @head.
+ * @extra_flags is or'd to work_struct flags.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
 static void insert_work(struct cpu_workqueue_struct *cwq,
-                        struct work_struct *work, struct list_head *head)
+                        struct work_struct *work, struct list_head *head,
+                        unsigned int extra_flags)
 {
-        trace_workqueue_insertion(cwq->thread, work);
+        struct global_cwq *gcwq = cwq->gcwq;
+
+        /* we own @work, set data and link */
+        set_work_cwq(work, cwq, extra_flags);
 
-        set_wq_data(work, cwq);
         /*
          * Ensure that we get the right work->data if we see the
          * result of list_add() below, see try_to_grab_pending().
          */
         smp_wmb();
+
         list_add_tail(&work->entry, head);
-        wake_up(&cwq->more_work);
+
+        /*
+         * Ensure either worker_sched_deactivated() sees the above
+         * list_add_tail() or we see zero nr_running to avoid workers
+         * lying around lazily while there are works to be processed.
+         */
+        smp_mb();
+
+        if (__need_more_worker(gcwq))
+                wake_up_worker(gcwq);
 }
 
-static void __queue_work(struct cpu_workqueue_struct *cwq,
+static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
                          struct work_struct *work)
 {
+        struct global_cwq *gcwq;
+        struct cpu_workqueue_struct *cwq;
+        struct list_head *worklist;
         unsigned long flags;
 
         debug_work_activate(work);
-        spin_lock_irqsave(&cwq->lock, flags);
-        insert_work(cwq, work, &cwq->worklist);
-        spin_unlock_irqrestore(&cwq->lock, flags);
+
+        /* determine gcwq to use */
+        if (!(wq->flags & WQ_UNBOUND)) {
+                struct global_cwq *last_gcwq;
+
+                if (unlikely(cpu == WORK_CPU_UNBOUND))
+                        cpu = raw_smp_processor_id();
+
+                /*
+                 * It's multi cpu.  If @wq is non-reentrant and @work
+                 * was previously on a different cpu, it might still
+                 * be running there, in which case the work needs to
+                 * be queued on that cpu to guarantee non-reentrance.
+                 */
+                gcwq = get_gcwq(cpu);
+                if (wq->flags & WQ_NON_REENTRANT &&
+                    (last_gcwq = get_work_gcwq(work)) && last_gcwq != gcwq) {
+                        struct worker *worker;
+
+                        spin_lock_irqsave(&last_gcwq->lock, flags);
+
+                        worker = find_worker_executing_work(last_gcwq, work);
+
+                        if (worker && worker->current_cwq->wq == wq)
+                                gcwq = last_gcwq;
+                        else {
+                                /* meh... not running there, queue here */
+                                spin_unlock_irqrestore(&last_gcwq->lock, flags);
+                                spin_lock_irqsave(&gcwq->lock, flags);
+                        }
+                } else
+                        spin_lock_irqsave(&gcwq->lock, flags);
+        } else {
+                gcwq = get_gcwq(WORK_CPU_UNBOUND);
+                spin_lock_irqsave(&gcwq->lock, flags);
+        }
+
+        /* gcwq determined, get cwq and queue */
+        cwq = get_cwq(gcwq->cpu, wq);
+
+        BUG_ON(!list_empty(&work->entry));
+
+        cwq->nr_in_flight[cwq->work_color]++;
+
+        if (likely(cwq->nr_active < cwq->max_active)) {
+                cwq->nr_active++;
+                worklist = gcwq_determine_ins_pos(gcwq, cwq);
+        } else
+                worklist = &cwq->delayed_works;
+
+        insert_work(cwq, work, worklist, work_color_to_flags(cwq->work_color));
+
+        spin_unlock_irqrestore(&gcwq->lock, flags);
 }
 
 /**
@@ -323,9 +1035,8 @@ queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
 {
         int ret = 0;
 
-        if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
-                BUG_ON(!list_empty(&work->entry));
-                __queue_work(wq_per_cpu(wq, cpu), work);
+        if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+                __queue_work(cpu, wq, work);
                 ret = 1;
         }
         return ret;
@@ -335,10 +1046,9 @@ EXPORT_SYMBOL_GPL(queue_work_on);
 static void delayed_work_timer_fn(unsigned long __data)
 {
         struct delayed_work *dwork = (struct delayed_work *)__data;
-        struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
-        struct workqueue_struct *wq = cwq->wq;
+        struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work);
 
-        __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work);
+        __queue_work(smp_processor_id(), cwq->wq, &dwork->work);
 }
 
 /**
@@ -375,14 +1085,31 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
         struct timer_list *timer = &dwork->timer;
         struct work_struct *work = &dwork->work;
 
-        if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
+        if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+                unsigned int lcpu;
+
                 BUG_ON(timer_pending(timer));
                 BUG_ON(!list_empty(&work->entry));
 
                 timer_stats_timer_set_start_info(&dwork->timer);
 
-                /* This stores cwq for the moment, for the timer_fn */
-                set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id()));
+                /*
+                 * This stores cwq for the moment, for the timer_fn.
+                 * Note that the work's gcwq is preserved to allow
+                 * reentrance detection for delayed works.
+                 */
+                if (!(wq->flags & WQ_UNBOUND)) {
+                        struct global_cwq *gcwq = get_work_gcwq(work);
+
+                        if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND)
+                                lcpu = gcwq->cpu;
+                        else
+                                lcpu = raw_smp_processor_id();
+                } else
+                        lcpu = WORK_CPU_UNBOUND;
+
+                set_work_cwq(work, get_cwq(lcpu, wq), 0);
+
                 timer->expires = jiffies + delay;
                 timer->data = (unsigned long)dwork;
                 timer->function = delayed_work_timer_fn;
@@ -397,80 +1124,872 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 }
 EXPORT_SYMBOL_GPL(queue_delayed_work_on);
 
-static void run_workqueue(struct cpu_workqueue_struct *cwq)
+/**
+ * worker_enter_idle - enter idle state
+ * @worker: worker which is entering idle state
+ *
+ * @worker is entering idle state.  Update stats and idle timer if
+ * necessary.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void worker_enter_idle(struct worker *worker)
 {
-        spin_lock_irq(&cwq->lock);
-        while (!list_empty(&cwq->worklist)) {
-                struct work_struct *work = list_entry(cwq->worklist.next,
-                                                struct work_struct, entry);
-                work_func_t f = work->func;
-#ifdef CONFIG_LOCKDEP
+        struct global_cwq *gcwq = worker->gcwq;
+
+        BUG_ON(worker->flags & WORKER_IDLE);
+        BUG_ON(!list_empty(&worker->entry) &&
+               (worker->hentry.next || worker->hentry.pprev));
+
+        /* can't use worker_set_flags(), also called from start_worker() */
+        worker->flags |= WORKER_IDLE;
+        gcwq->nr_idle++;
+        worker->last_active = jiffies;
+
+        /* idle_list is LIFO */
+        list_add(&worker->entry, &gcwq->idle_list);
+
+        if (likely(!(worker->flags & WORKER_ROGUE))) {
+                if (too_many_workers(gcwq) && !timer_pending(&gcwq->idle_timer))
+                        mod_timer(&gcwq->idle_timer,
+                                  jiffies + IDLE_WORKER_TIMEOUT);
+        } else
+                wake_up_all(&gcwq->trustee_wait);
+
+        /* sanity check nr_running */
+        WARN_ON_ONCE(gcwq->nr_workers == gcwq->nr_idle &&
+                     atomic_read(get_gcwq_nr_running(gcwq->cpu)));
+}
+
+/**
+ * worker_leave_idle - leave idle state
+ * @worker: worker which is leaving idle state
+ *
+ * @worker is leaving idle state.  Update stats.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void worker_leave_idle(struct worker *worker)
+{
+        struct global_cwq *gcwq = worker->gcwq;
+
+        BUG_ON(!(worker->flags & WORKER_IDLE));
+        worker_clr_flags(worker, WORKER_IDLE);
+        gcwq->nr_idle--;
+        list_del_init(&worker->entry);
+}
+
+/**
+ * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq
+ * @worker: self
+ *
+ * Works which are scheduled while the cpu is online must at least be
+ * scheduled to a worker which is bound to the cpu so that if they are
+ * flushed from cpu callbacks while cpu is going down, they are
+ * guaranteed to execute on the cpu.
+ *
+ * This function is to be used by rogue workers and rescuers to bind
+ * themselves to the target cpu and may race with cpu going down or
+ * coming online.  kthread_bind() can't be used because it may put the
+ * worker to already dead cpu and set_cpus_allowed_ptr() can't be used
+ * verbatim as it's best effort and blocking and gcwq may be
+ * [dis]associated in the meantime.
+ *
+ * This function tries set_cpus_allowed() and locks gcwq and verifies
+ * the binding against GCWQ_DISASSOCIATED which is set during
+ * CPU_DYING and cleared during CPU_ONLINE, so if the worker enters
+ * idle state or fetches works without dropping lock, it can guarantee
+ * the scheduling requirement described in the first paragraph.
+ *
+ * CONTEXT:
+ * Might sleep.  Called without any lock but returns with gcwq->lock
+ * held.
+ *
+ * RETURNS:
+ * %true if the associated gcwq is online (@worker is successfully
+ * bound), %false if offline.
+ */
+static bool worker_maybe_bind_and_lock(struct worker *worker)
+{
+        struct global_cwq *gcwq = worker->gcwq;
+        struct task_struct *task = worker->task;
+
+        while (true) {
                 /*
-                 * It is permissible to free the struct work_struct
-                 * from inside the function that is called from it,
-                 * this we need to take into account for lockdep too.
-                 * To avoid bogus "held lock freed" warnings as well
-                 * as problems when looking into work->lockdep_map,
-                 * make a copy and use that here.
+                 * The following call may fail, succeed or succeed
+                 * without actually migrating the task to the cpu if
+                 * it races with cpu hotunplug operation.  Verify
+                 * against GCWQ_DISASSOCIATED.
                  */
-                struct lockdep_map lockdep_map = work->lockdep_map;
-#endif
-                trace_workqueue_execution(cwq->thread, work);
-                debug_work_deactivate(work);
-                cwq->current_work = work;
-                list_del_init(cwq->worklist.next);
-                spin_unlock_irq(&cwq->lock);
-
-                BUG_ON(get_wq_data(work) != cwq);
-                work_clear_pending(work);
-                lock_map_acquire(&cwq->wq->lockdep_map);
-                lock_map_acquire(&lockdep_map);
-                f(work);
-                lock_map_release(&lockdep_map);
-                lock_map_release(&cwq->wq->lockdep_map);
-
-                if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
-                        printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
-                                        "%s/0x%08x/%d\n",
-                                        current->comm, preempt_count(),
-                                        task_pid_nr(current));
-                        printk(KERN_ERR "    last function: ");
-                        print_symbol("%s\n", (unsigned long)f);
-                        debug_show_held_locks(current);
-                        dump_stack();
+                if (!(gcwq->flags & GCWQ_DISASSOCIATED))
+                        set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu));
+
+                spin_lock_irq(&gcwq->lock);
+                if (gcwq->flags & GCWQ_DISASSOCIATED)
+                        return false;
+                if (task_cpu(task) == gcwq->cpu &&
+                    cpumask_equal(&current->cpus_allowed,
+                                  get_cpu_mask(gcwq->cpu)))
+                        return true;
+                spin_unlock_irq(&gcwq->lock);
+
+                /* CPU has come up inbetween, retry migration */
+                cpu_relax();
+        }
+}
+
+/*
+ * Function for worker->rebind_work used to rebind rogue busy workers
+ * to the associated cpu which is coming back online.  This is
+ * scheduled by cpu up but can race with other cpu hotplug operations
+ * and may be executed twice without intervening cpu down.
+ */
+static void worker_rebind_fn(struct work_struct *work)
+{
+        struct worker *worker = container_of(work, struct worker, rebind_work);
+        struct global_cwq *gcwq = worker->gcwq;
+
+        if (worker_maybe_bind_and_lock(worker))
+                worker_clr_flags(worker, WORKER_REBIND);
+
+        spin_unlock_irq(&gcwq->lock);
+}
+
+static struct worker *alloc_worker(void)
+{
+        struct worker *worker;
+
+        worker = kzalloc(sizeof(*worker), GFP_KERNEL);
+        if (worker) {
+                INIT_LIST_HEAD(&worker->entry);
+                INIT_LIST_HEAD(&worker->scheduled);
+                INIT_WORK(&worker->rebind_work, worker_rebind_fn);
+                /* on creation a worker is in !idle && prep state */
+                worker->flags = WORKER_PREP;
+        }
+        return worker;
+}
+
+/**
+ * create_worker - create a new workqueue worker
+ * @gcwq: gcwq the new worker will belong to
+ * @bind: whether to set affinity to @cpu or not
+ *
+ * Create a new worker which is bound to @gcwq.  The returned worker
+ * can be started by calling start_worker() or destroyed using
+ * destroy_worker().
+ *
+ * CONTEXT:
+ * Might sleep.  Does GFP_KERNEL allocations.
+ *
+ * RETURNS:
+ * Pointer to the newly created worker.
+ */
+static struct worker *create_worker(struct global_cwq *gcwq, bool bind)
+{
+        bool on_unbound_cpu = gcwq->cpu == WORK_CPU_UNBOUND;
+        struct worker *worker = NULL;
+        int id = -1;
+
+        spin_lock_irq(&gcwq->lock);
+        while (ida_get_new(&gcwq->worker_ida, &id)) {
+                spin_unlock_irq(&gcwq->lock);
+                if (!ida_pre_get(&gcwq->worker_ida, GFP_KERNEL))
+                        goto fail;
+                spin_lock_irq(&gcwq->lock);
+        }
+        spin_unlock_irq(&gcwq->lock);
+
+        worker = alloc_worker();
+        if (!worker)
+                goto fail;
+
+        worker->gcwq = gcwq;
+        worker->id = id;
+
+        if (!on_unbound_cpu)
+                worker->task = kthread_create(worker_thread, worker,
+                                              "kworker/%u:%d", gcwq->cpu, id);
+        else
+                worker->task = kthread_create(worker_thread, worker,
+                                              "kworker/u:%d", id);
+        if (IS_ERR(worker->task))
+                goto fail;
+
+        /*
+         * A rogue worker will become a regular one if CPU comes
+         * online later on.  Make sure every worker has
+         * PF_THREAD_BOUND set.
+         */
+        if (bind && !on_unbound_cpu)
+                kthread_bind(worker->task, gcwq->cpu);
+        else {
+                worker->task->flags |= PF_THREAD_BOUND;
+                if (on_unbound_cpu)
+                        worker->flags |= WORKER_UNBOUND;
+        }
+
+        return worker;
+fail:
+        if (id >= 0) {
+                spin_lock_irq(&gcwq->lock);
+                ida_remove(&gcwq->worker_ida, id);
+                spin_unlock_irq(&gcwq->lock);
+        }
+        kfree(worker);
+        return NULL;
+}
+
+/**
+ * start_worker - start a newly created worker
+ * @worker: worker to start
+ *
+ * Make the gcwq aware of @worker and start it.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void start_worker(struct worker *worker)
+{
+        worker->flags |= WORKER_STARTED;
+        worker->gcwq->nr_workers++;
+        worker_enter_idle(worker);
+        wake_up_process(worker->task);
+}
+
+/**
+ * destroy_worker - destroy a workqueue worker
+ * @worker: worker to be destroyed
+ *
+ * Destroy @worker and adjust @gcwq stats accordingly.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which is released and regrabbed.
+ */
+static void destroy_worker(struct worker *worker)
+{
+        struct global_cwq *gcwq = worker->gcwq;
+        int id = worker->id;
+
+        /* sanity check frenzy */
+        BUG_ON(worker->current_work);
+        BUG_ON(!list_empty(&worker->scheduled));
+
+        if (worker->flags & WORKER_STARTED)
+                gcwq->nr_workers--;
+        if (worker->flags & WORKER_IDLE)
+                gcwq->nr_idle--;
+
+        list_del_init(&worker->entry);
+        worker->flags |= WORKER_DIE;
+
+        spin_unlock_irq(&gcwq->lock);
+
+        kthread_stop(worker->task);
+        kfree(worker);
+
+        spin_lock_irq(&gcwq->lock);
+        ida_remove(&gcwq->worker_ida, id);
+}
+
+static void idle_worker_timeout(unsigned long __gcwq)
+{
+        struct global_cwq *gcwq = (void *)__gcwq;
+
+        spin_lock_irq(&gcwq->lock);
+
+        if (too_many_workers(gcwq)) {
+                struct worker *worker;
+                unsigned long expires;
+
+                /* idle_list is kept in LIFO order, check the last one */
+                worker = list_entry(gcwq->idle_list.prev, struct worker, entry);
+                expires = worker->last_active + IDLE_WORKER_TIMEOUT;
+
+                if (time_before(jiffies, expires))
+                        mod_timer(&gcwq->idle_timer, expires);
+                else {
+                        /* it's been idle for too long, wake up manager */
+                        gcwq->flags |= GCWQ_MANAGE_WORKERS;
+                        wake_up_worker(gcwq);
+                }
+        }
+
+        spin_unlock_irq(&gcwq->lock);
+}
+
+static bool send_mayday(struct work_struct *work)
+{
+        struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+        struct workqueue_struct *wq = cwq->wq;
+        unsigned int cpu;
+
+        if (!(wq->flags & WQ_RESCUER))
+                return false;
+
+        /* mayday mayday mayday */
+        cpu = cwq->gcwq->cpu;
+        /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */
+        if (cpu == WORK_CPU_UNBOUND)
+                cpu = 0;
+        if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask))
+                wake_up_process(wq->rescuer->task);
+        return true;
+}
+
+static void gcwq_mayday_timeout(unsigned long __gcwq)
+{
+        struct global_cwq *gcwq = (void *)__gcwq;
+        struct work_struct *work;
+
+        spin_lock_irq(&gcwq->lock);
+
+        if (need_to_create_worker(gcwq)) {
+                /*
+                 * We've been trying to create a new worker but
+                 * haven't been successful.  We might be hitting an
+                 * allocation deadlock.  Send distress signals to
+                 * rescuers.
+                 */
+                list_for_each_entry(work, &gcwq->worklist, entry)
+                        send_mayday(work);
+        }
+
+        spin_unlock_irq(&gcwq->lock);
+
+        mod_timer(&gcwq->mayday_timer, jiffies + MAYDAY_INTERVAL);
+}
+
+/**
+ * maybe_create_worker - create a new worker if necessary
+ * @gcwq: gcwq to create a new worker for
+ *
+ * Create a new worker for @gcwq if necessary.  @gcwq is guaranteed to
+ * have at least one idle worker on return from this function.  If
+ * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
+ * sent to all rescuers with works scheduled on @gcwq to resolve
+ * possible allocation deadlock.
+ *
+ * On return, need_to_create_worker() is guaranteed to be false and
+ * may_start_working() true.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.  Does GFP_KERNEL allocations.  Called only from
+ * manager.
+ *
+ * RETURNS:
+ * false if no action was taken and gcwq->lock stayed locked, true
+ * otherwise.
+ */
+static bool maybe_create_worker(struct global_cwq *gcwq)
+{
+        if (!need_to_create_worker(gcwq))
+                return false;
+restart:
+        spin_unlock_irq(&gcwq->lock);
+
+        /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
+        mod_timer(&gcwq->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
+
+        while (true) {
+                struct worker *worker;
+
+                worker = create_worker(gcwq, true);
+                if (worker) {
+                        del_timer_sync(&gcwq->mayday_timer);
+                        spin_lock_irq(&gcwq->lock);
+                        start_worker(worker);
+                        BUG_ON(need_to_create_worker(gcwq));
+                        return true;
+                }
+
+                if (!need_to_create_worker(gcwq))
+                        break;
+
+                __set_current_state(TASK_INTERRUPTIBLE);
+                schedule_timeout(CREATE_COOLDOWN);
+
+                if (!need_to_create_worker(gcwq))
+                        break;
+        }
+
+        del_timer_sync(&gcwq->mayday_timer);
+        spin_lock_irq(&gcwq->lock);
+        if (need_to_create_worker(gcwq))
+                goto restart;
+        return true;
+}
+
+/**
+ * maybe_destroy_worker - destroy workers which have been idle for a while
+ * @gcwq: gcwq to destroy workers for
+ *
+ * Destroy @gcwq workers which have been idle for longer than
+ * IDLE_WORKER_TIMEOUT.
+ *
+ * LOCKING:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.  Called only from manager.
+ *
+ * RETURNS:
+ * false if no action was taken and gcwq->lock stayed locked, true
+ * otherwise.
+ */
+static bool maybe_destroy_workers(struct global_cwq *gcwq)
+{
+        bool ret = false;
+
+        while (too_many_workers(gcwq)) {
+                struct worker *worker;
+                unsigned long expires;
+
+                worker = list_entry(gcwq->idle_list.prev, struct worker, entry);
+                expires = worker->last_active + IDLE_WORKER_TIMEOUT;
+
+                if (time_before(jiffies, expires)) {
+                        mod_timer(&gcwq->idle_timer, expires);
+                        break;
                 }
 
-                spin_lock_irq(&cwq->lock);
-                cwq->current_work = NULL;
+                destroy_worker(worker);
+                ret = true;
         }
-        spin_unlock_irq(&cwq->lock);
+
+        return ret;
 }
 
-static int worker_thread(void *__cwq)
+/**
+ * manage_workers - manage worker pool
+ * @worker: self
+ *
+ * Assume the manager role and manage gcwq worker pool @worker belongs
+ * to.  At any given time, there can be only zero or one manager per
+ * gcwq.  The exclusion is handled automatically by this function.
+ *
+ * The caller can safely start processing works on false return.  On
+ * true return, it's guaranteed that need_to_create_worker() is false
+ * and may_start_working() is true.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.  Does GFP_KERNEL allocations.
+ *
+ * RETURNS:
+ * false if no action was taken and gcwq->lock stayed locked, true if
+ * some action was taken.
+ */
+static bool manage_workers(struct worker *worker)
 {
-        struct cpu_workqueue_struct *cwq = __cwq;
-        DEFINE_WAIT(wait);
+        struct global_cwq *gcwq = worker->gcwq;
+        bool ret = false;
 
-        if (cwq->wq->freezeable)
-                set_freezable();
+        if (gcwq->flags & GCWQ_MANAGING_WORKERS)
+                return ret;
 
-        for (;;) {
-                prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
-                if (!freezing(current) &&
-                    !kthread_should_stop() &&
-                    list_empty(&cwq->worklist))
-                        schedule();
-                finish_wait(&cwq->more_work, &wait);
+        gcwq->flags &= ~GCWQ_MANAGE_WORKERS;
+        gcwq->flags |= GCWQ_MANAGING_WORKERS;
 
-                try_to_freeze();
+        /*
+         * Destroy and then create so that may_start_working() is true
+         * on return.
+         */
+        ret |= maybe_destroy_workers(gcwq);
+        ret |= maybe_create_worker(gcwq);
+
+        gcwq->flags &= ~GCWQ_MANAGING_WORKERS;
+
+        /*
+         * The trustee might be waiting to take over the manager
+         * position, tell it we're done.
+         */
+        if (unlikely(gcwq->trustee))
+                wake_up_all(&gcwq->trustee_wait);
+
+        return ret;
+}
+
+/**
+ * move_linked_works - move linked works to a list
+ * @work: start of series of works to be scheduled
+ * @head: target list to append @work to
+ * @nextp: out paramter for nested worklist walking
+ *
+ * Schedule linked works starting from @work to @head.  Work series to
+ * be scheduled starts at @work and includes any consecutive work with
+ * WORK_STRUCT_LINKED set in its predecessor.
+ *
+ * If @nextp is not NULL, it's updated to point to the next work of
+ * the last scheduled work.  This allows move_linked_works() to be
+ * nested inside outer list_for_each_entry_safe().
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void move_linked_works(struct work_struct *work, struct list_head *head,
+                              struct work_struct **nextp)
+{
+        struct work_struct *n;
 
-                if (kthread_should_stop())
+        /*
+         * Linked worklist will always end before the end of the list,
+         * use NULL for list head.
+         */
+        list_for_each_entry_safe_from(work, n, NULL, entry) {
+                list_move_tail(&work->entry, head);
+                if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
                         break;
+        }
+
+        /*
+         * If we're already inside safe list traversal and have moved
+         * multiple works to the scheduled queue, the next position
+         * needs to be updated.
+         */
+        if (nextp)
+                *nextp = n;
+}
 
-                run_workqueue(cwq);
+static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
+{
+        struct work_struct *work = list_first_entry(&cwq->delayed_works,
+                                                    struct work_struct, entry);
+        struct list_head *pos = gcwq_determine_ins_pos(cwq->gcwq, cwq);
+
+        move_linked_works(work, pos, NULL);
+        cwq->nr_active++;
+}
+
+/**
+ * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
+ * @cwq: cwq of interest
+ * @color: color of work which left the queue
+ *
+ * A work either has completed or is removed from pending queue,
+ * decrement nr_in_flight of its cwq and handle workqueue flushing.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
+{
+        /* ignore uncolored works */
+        if (color == WORK_NO_COLOR)
+                return;
+
+        cwq->nr_in_flight[color]--;
+        cwq->nr_active--;
+
+        if (!list_empty(&cwq->delayed_works)) {
+                /* one down, submit a delayed one */
+                if (cwq->nr_active < cwq->max_active)
+                        cwq_activate_first_delayed(cwq);
         }
 
-        return 0;
+        /* is flush in progress and are we at the flushing tip? */
+        if (likely(cwq->flush_color != color))
+                return;
+
+        /* are there still in-flight works? */
+        if (cwq->nr_in_flight[color])
+                return;
+
+        /* this cwq is done, clear flush_color */
+        cwq->flush_color = -1;
+
+        /*
+         * If this was the last cwq, wake up the first flusher.  It
+         * will handle the rest.
+         */
+        if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush))
+                complete(&cwq->wq->first_flusher->done);
+}
+
+/**
+ * process_one_work - process single work
+ * @worker: self
+ * @work: work to process
+ *
+ * Process @work.  This function contains all the logics necessary to
+ * process a single work including synchronization against and
+ * interaction with other workers on the same cpu, queueing and
+ * flushing.  As long as context requirement is met, any worker can
+ * call this function to process a work.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which is released and regrabbed.
+ */
+static void process_one_work(struct worker *worker, struct work_struct *work)
+{
+        struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+        struct global_cwq *gcwq = cwq->gcwq;
+        struct hlist_head *bwh = busy_worker_head(gcwq, work);
+        bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE;
+        work_func_t f = work->func;
+        int work_color;
+        struct worker *collision;
+#ifdef CONFIG_LOCKDEP
+        /*
+         * It is permissible to free the struct work_struct from
+         * inside the function that is called from it, this we need to
+         * take into account for lockdep too.  To avoid bogus "held
+         * lock freed" warnings as well as problems when looking into
+         * work->lockdep_map, make a copy and use that here.
+         */
+        struct lockdep_map lockdep_map = work->lockdep_map;
+#endif
+        /*
+         * A single work shouldn't be executed concurrently by
+         * multiple workers on a single cpu.  Check whether anyone is
+         * already processing the work.  If so, defer the work to the
+         * currently executing one.
+         */
+        collision = __find_worker_executing_work(gcwq, bwh, work);
+        if (unlikely(collision)) {
+                move_linked_works(work, &collision->scheduled, NULL);
+                return;
+        }
+
+        /* claim and process */
+        debug_work_deactivate(work);
+        hlist_add_head(&worker->hentry, bwh);
+        worker->current_work = work;
+        worker->current_cwq = cwq;
+        work_color = get_work_color(work);
+
+        /* record the current cpu number in the work data and dequeue */
+        set_work_cpu(work, gcwq->cpu);
+        list_del_init(&work->entry);
+
+        /*
+         * If HIGHPRI_PENDING, check the next work, and, if HIGHPRI,
+         * wake up another worker; otherwise, clear HIGHPRI_PENDING.
+         */
+        if (unlikely(gcwq->flags & GCWQ_HIGHPRI_PENDING)) {
+                struct work_struct *nwork = list_first_entry(&gcwq->worklist,
+                                                struct work_struct, entry);
+
+                if (!list_empty(&gcwq->worklist) &&
+                    get_work_cwq(nwork)->wq->flags & WQ_HIGHPRI)
+                        wake_up_worker(gcwq);
+                else
+                        gcwq->flags &= ~GCWQ_HIGHPRI_PENDING;
+        }
+
+        /*
+         * CPU intensive works don't participate in concurrency
+         * management.  They're the scheduler's responsibility.
+         */
+        if (unlikely(cpu_intensive))
+                worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);
+
+        spin_unlock_irq(&gcwq->lock);
+
+        work_clear_pending(work);
+        lock_map_acquire(&cwq->wq->lockdep_map);
+        lock_map_acquire(&lockdep_map);
+        f(work);
+        lock_map_release(&lockdep_map);
+        lock_map_release(&cwq->wq->lockdep_map);
+
+        if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
+                printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
+                       "%s/0x%08x/%d\n",
+                       current->comm, preempt_count(), task_pid_nr(current));
+                printk(KERN_ERR "    last function: ");
+                print_symbol("%s\n", (unsigned long)f);
+                debug_show_held_locks(current);
+                dump_stack();
+        }
+
+        spin_lock_irq(&gcwq->lock);
+
+        /* clear cpu intensive status */
+        if (unlikely(cpu_intensive))
+                worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
+
+        /* we're done with it, release */
+        hlist_del_init(&worker->hentry);
+        worker->current_work = NULL;
+        worker->current_cwq = NULL;
+        cwq_dec_nr_in_flight(cwq, work_color);
+}
+
+/**
+ * process_scheduled_works - process scheduled works
+ * @worker: self
+ *
+ * Process all scheduled works.  Please note that the scheduled list
+ * may change while processing a work, so this function repeatedly
+ * fetches a work from the top and executes it.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.
+ */
+static void process_scheduled_works(struct worker *worker)
+{
+        while (!list_empty(&worker->scheduled)) {
+                struct work_struct *work = list_first_entry(&worker->scheduled,
+                                                struct work_struct, entry);
+                process_one_work(worker, work);
+        }
+}
+
+/**
+ * worker_thread - the worker thread function
+ * @__worker: self
+ *
+ * The gcwq worker thread function.  There's a single dynamic pool of
+ * these per each cpu.  These workers process all works regardless of
+ * their specific target workqueue.  The only exception is works which
+ * belong to workqueues with a rescuer which will be explained in
+ * rescuer_thread().
+ */
+static int worker_thread(void *__worker)
+{
+        struct worker *worker = __worker;
+        struct global_cwq *gcwq = worker->gcwq;
+
+        /* tell the scheduler that this is a workqueue worker */
+        worker->task->flags |= PF_WQ_WORKER;
+woke_up:
+        spin_lock_irq(&gcwq->lock);
+
+        /* DIE can be set only while we're idle, checking here is enough */
+        if (worker->flags & WORKER_DIE) {
+                spin_unlock_irq(&gcwq->lock);
+                worker->task->flags &= ~PF_WQ_WORKER;
+                return 0;
+        }
+
+        worker_leave_idle(worker);
+recheck:
+        /* no more worker necessary? */
+        if (!need_more_worker(gcwq))
+                goto sleep;
+
+        /* do we need to manage? */
+        if (unlikely(!may_start_working(gcwq)) && manage_workers(worker))
+                goto recheck;
+
+        /*
+         * ->scheduled list can only be filled while a worker is
+         * preparing to process a work or actually processing it.
+         * Make sure nobody diddled with it while I was sleeping.
+         */
+        BUG_ON(!list_empty(&worker->scheduled));
+
+        /*
+         * When control reaches this point, we're guaranteed to have
+         * at least one idle worker or that someone else has already
+         * assumed the manager role.
+         */
+        worker_clr_flags(worker, WORKER_PREP);
+
+        do {
+                struct work_struct *work =
+                        list_first_entry(&gcwq->worklist,
+                                         struct work_struct, entry);
+
+                if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) {
+                        /* optimization path, not strictly necessary */
+                        process_one_work(worker, work);
+                        if (unlikely(!list_empty(&worker->scheduled)))
+                                process_scheduled_works(worker);
+                } else {
+                        move_linked_works(work, &worker->scheduled, NULL);
+                        process_scheduled_works(worker);
+                }
+        } while (keep_working(gcwq));
+
+        worker_set_flags(worker, WORKER_PREP, false);
+sleep:
+        if (unlikely(need_to_manage_workers(gcwq)) && manage_workers(worker))
+                goto recheck;
+
+        /*
+         * gcwq->lock is held and there's no work to process and no
+         * need to manage, sleep.  Workers are woken up only while
+         * holding gcwq->lock or from local cpu, so setting the
+         * current state before releasing gcwq->lock is enough to
+         * prevent losing any event.
+         */
+        worker_enter_idle(worker);
+        __set_current_state(TASK_INTERRUPTIBLE);
+        spin_unlock_irq(&gcwq->lock);
+        schedule();
+        goto woke_up;
+}
+
+/**
+ * rescuer_thread - the rescuer thread function
+ * @__wq: the associated workqueue
+ *
+ * Workqueue rescuer thread function.  There's one rescuer for each
+ * workqueue which has WQ_RESCUER set.
+ *
+ * Regular work processing on a gcwq may block trying to create a new
+ * worker which uses GFP_KERNEL allocation which has slight chance of
+ * developing into deadlock if some works currently on the same queue
+ * need to be processed to satisfy the GFP_KERNEL allocation.  This is
+ * the problem rescuer solves.
+ *
+ * When such condition is possible, the gcwq summons rescuers of all
+ * workqueues which have works queued on the gcwq and let them process
+ * those works so that forward progress can be guaranteed.
+ *
+ * This should happen rarely.
+ */
+static int rescuer_thread(void *__wq)
+{
+        struct workqueue_struct *wq = __wq;
+        struct worker *rescuer = wq->rescuer;
+        struct list_head *scheduled = &rescuer->scheduled;
+        bool is_unbound = wq->flags & WQ_UNBOUND;
+        unsigned int cpu;
+
+        set_user_nice(current, RESCUER_NICE_LEVEL);
+repeat:
+        set_current_state(TASK_INTERRUPTIBLE);
+
+        if (kthread_should_stop())
+                return 0;
+
+        /*
+         * See whether any cpu is asking for help.  Unbounded
+         * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND.
+         */
+        for_each_mayday_cpu(cpu, wq->mayday_mask) {
+                unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu;
+                struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq);
+                struct global_cwq *gcwq = cwq->gcwq;
+                struct work_struct *work, *n;
+
+                __set_current_state(TASK_RUNNING);
+                mayday_clear_cpu(cpu, wq->mayday_mask);
+
+                /* migrate to the target cpu if possible */
+                rescuer->gcwq = gcwq;
+                worker_maybe_bind_and_lock(rescuer);
+
+                /*
+                 * Slurp in all works issued via this workqueue and
+                 * process'em.
+                 */
+                BUG_ON(!list_empty(&rescuer->scheduled));
+                list_for_each_entry_safe(work, n, &gcwq->worklist, entry)
+                        if (get_work_cwq(work) == cwq)
+                                move_linked_works(work, scheduled, &n);
+
+                process_scheduled_works(rescuer);
+                spin_unlock_irq(&gcwq->lock);
+        }
+
+        schedule();
+        goto repeat;
 }
 
 struct wq_barrier {
@@ -484,44 +2003,137 @@ static void wq_barrier_func(struct work_struct *work)
         complete(&barr->done);
 }
 
+/**
+ * insert_wq_barrier - insert a barrier work
+ * @cwq: cwq to insert barrier into
+ * @barr: wq_barrier to insert
+ * @target: target work to attach @barr to
+ * @worker: worker currently executing @target, NULL if @target is not executing
+ *
+ * @barr is linked to @target such that @barr is completed only after
+ * @target finishes execution.  Please note that the ordering
+ * guarantee is observed only with respect to @target and on the local
+ * cpu.
+ *
+ * Currently, a queued barrier can't be canceled.  This is because
+ * try_to_grab_pending() can't determine whether the work to be
+ * grabbed is at the head of the queue and thus can't clear LINKED
+ * flag of the previous work while there must be a valid next work
+ * after a work with LINKED flag set.
+ *
+ * Note that when @worker is non-NULL, @target may be modified
+ * underneath us, so we can't reliably determine cwq from @target.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
 static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
-                        struct wq_barrier *barr, struct list_head *head)
+                              struct wq_barrier *barr,
+                              struct work_struct *target, struct worker *worker)
 {
+        struct list_head *head;
+        unsigned int linked = 0;
+
         /*
-         * debugobject calls are safe here even with cwq->lock locked
+         * debugobject calls are safe here even with gcwq->lock locked
          * as we know for sure that this will not trigger any of the
          * checks and call back into the fixup functions where we
          * might deadlock.
          */
         INIT_WORK_ON_STACK(&barr->work, wq_barrier_func);
-        __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work));
-
+        __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
         init_completion(&barr->done);
 
+        /*
+         * If @target is currently being executed, schedule the
+         * barrier to the worker; otherwise, put it after @target.
+         */
+        if (worker)
+                head = worker->scheduled.next;
+        else {
+                unsigned long *bits = work_data_bits(target);
+
+                head = target->entry.next;
+                /* there can already be other linked works, inherit and set */
+                linked = *bits & WORK_STRUCT_LINKED;
+                __set_bit(WORK_STRUCT_LINKED_BIT, bits);
+        }
+
         debug_work_activate(&barr->work);
-        insert_work(cwq, &barr->work, head);
+        insert_work(cwq, &barr->work, head,
+                    work_color_to_flags(WORK_NO_COLOR) | linked);
 }
 
-static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
+/**
+ * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing
+ * @wq: workqueue being flushed
+ * @flush_color: new flush color, < 0 for no-op
+ * @work_color: new work color, < 0 for no-op
+ *
+ * Prepare cwqs for workqueue flushing.
+ *
+ * If @flush_color is non-negative, flush_color on all cwqs should be
+ * -1.  If no cwq has in-flight commands at the specified color, all
+ * cwq->flush_color's stay at -1 and %false is returned.  If any cwq
+ * has in flight commands, its cwq->flush_color is set to
+ * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq
+ * wakeup logic is armed and %true is returned.
+ *
+ * The caller should have initialized @wq->first_flusher prior to
+ * calling this function with non-negative @flush_color.  If
+ * @flush_color is negative, no flush color update is done and %false
+ * is returned.
+ *
+ * If @work_color is non-negative, all cwqs should have the same
+ * work_color which is previous to @work_color and all will be
+ * advanced to @work_color.
+ *
+ * CONTEXT:
+ * mutex_lock(wq->flush_mutex).
+ *
+ * RETURNS:
+ * %true if @flush_color >= 0 and there's something to flush.  %false
+ * otherwise.
+ */
+static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
+                                      int flush_color, int work_color)
 {
-        int active = 0;
-        struct wq_barrier barr;
-
-        WARN_ON(cwq->thread == current);
+        bool wait = false;
+        unsigned int cpu;
 
-        spin_lock_irq(&cwq->lock);
-        if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
-                insert_wq_barrier(cwq, &barr, &cwq->worklist);
-                active = 1;
+        if (flush_color >= 0) {
+                BUG_ON(atomic_read(&wq->nr_cwqs_to_flush));
+                atomic_set(&wq->nr_cwqs_to_flush, 1);
         }
-        spin_unlock_irq(&cwq->lock);
 
-        if (active) {
-                wait_for_completion(&barr.done);
-                destroy_work_on_stack(&barr.work);
+        for_each_cwq_cpu(cpu, wq) {
+                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                struct global_cwq *gcwq = cwq->gcwq;
+
+                spin_lock_irq(&gcwq->lock);
+
+                if (flush_color >= 0) {
+                        BUG_ON(cwq->flush_color != -1);
+
+                        if (cwq->nr_in_flight[flush_color]) {
+                                cwq->flush_color = flush_color;
+                                atomic_inc(&wq->nr_cwqs_to_flush);
+                                wait = true;
+                        }
+                }
+
+                if (work_color >= 0) {
+                        BUG_ON(work_color != work_next_color(cwq->work_color));
+                        cwq->work_color = work_color;
+                }
+
+                spin_unlock_irq(&gcwq->lock);
         }
 
-        return active;
+        if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush))
+                complete(&wq->first_flusher->done);
+
+        return wait;
 }
 
 /**
@@ -533,20 +2145,150 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
  *
  * We sleep until all works which were queued on entry have been handled,
  * but we are not livelocked by new incoming ones.
- *
- * This function used to run the workqueues itself.  Now we just wait for the
- * helper threads to do it.
  */
 void flush_workqueue(struct workqueue_struct *wq)
 {
-        const struct cpumask *cpu_map = wq_cpu_map(wq);
-        int cpu;
+        struct wq_flusher this_flusher = {
+                .list = LIST_HEAD_INIT(this_flusher.list),
+                .flush_color = -1,
+                .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done),
+        };
+        int next_color;
 
-        might_sleep();
         lock_map_acquire(&wq->lockdep_map);
         lock_map_release(&wq->lockdep_map);
-        for_each_cpu(cpu, cpu_map)
-                flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
+
+        mutex_lock(&wq->flush_mutex);
+
+        /*
+         * Start-to-wait phase
+         */
+        next_color = work_next_color(wq->work_color);
+
+        if (next_color != wq->flush_color) {
+                /*
+                 * Color space is not full.  The current work_color
+                 * becomes our flush_color and work_color is advanced
+                 * by one.
+                 */
+                BUG_ON(!list_empty(&wq->flusher_overflow));
+                this_flusher.flush_color = wq->work_color;
+                wq->work_color = next_color;
+
+                if (!wq->first_flusher) {
+                        /* no flush in progress, become the first flusher */
+                        BUG_ON(wq->flush_color != this_flusher.flush_color);
+
+                        wq->first_flusher = &this_flusher;
+
+                        if (!flush_workqueue_prep_cwqs(wq, wq->flush_color,
+                                                       wq->work_color)) {
+                                /* nothing to flush, done */
+                                wq->flush_color = next_color;
+                                wq->first_flusher = NULL;
+                                goto out_unlock;
+                        }
+                } else {
+                        /* wait in queue */
+                        BUG_ON(wq->flush_color == this_flusher.flush_color);
+                        list_add_tail(&this_flusher.list, &wq->flusher_queue);
+                        flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+                }
+        } else {
+                /*
+                 * Oops, color space is full, wait on overflow queue.
+                 * The next flush completion will assign us
+                 * flush_color and transfer to flusher_queue.
+                 */
+                list_add_tail(&this_flusher.list, &wq->flusher_overflow);
+        }
+
+        mutex_unlock(&wq->flush_mutex);
+
+        wait_for_completion(&this_flusher.done);
+
+        /*
+         * Wake-up-and-cascade phase
+         *
+         * First flushers are responsible for cascading flushes and
+         * handling overflow.  Non-first flushers can simply return.
+         */
+        if (wq->first_flusher != &this_flusher)
+                return;
+
+        mutex_lock(&wq->flush_mutex);
+
+        /* we might have raced, check again with mutex held */
+        if (wq->first_flusher != &this_flusher)
+                goto out_unlock;
+
+        wq->first_flusher = NULL;
+
+        BUG_ON(!list_empty(&this_flusher.list));
+        BUG_ON(wq->flush_color != this_flusher.flush_color);
+
+        while (true) {
+                struct wq_flusher *next, *tmp;
+
+                /* complete all the flushers sharing the current flush color */
+                list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) {
+                        if (next->flush_color != wq->flush_color)
+                                break;
+                        list_del_init(&next->list);
+                        complete(&next->done);
+                }
+
+                BUG_ON(!list_empty(&wq->flusher_overflow) &&
+                       wq->flush_color != work_next_color(wq->work_color));
+
+                /* this flush_color is finished, advance by one */
+                wq->flush_color = work_next_color(wq->flush_color);
+
+                /* one color has been freed, handle overflow queue */
+                if (!list_empty(&wq->flusher_overflow)) {
+                        /*
+                         * Assign the same color to all overflowed
+                         * flushers, advance work_color and append to
+                         * flusher_queue.  This is the start-to-wait
+                         * phase for these overflowed flushers.
+                         */
+                        list_for_each_entry(tmp, &wq->flusher_overflow, list)
+                                tmp->flush_color = wq->work_color;
+
+                        wq->work_color = work_next_color(wq->work_color);
+
+                        list_splice_tail_init(&wq->flusher_overflow,
+                                              &wq->flusher_queue);
+                        flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+                }
+
+                if (list_empty(&wq->flusher_queue)) {
+                        BUG_ON(wq->flush_color != wq->work_color);
+                        break;
+                }
+
+                /*
+                 * Need to flush more colors.  Make the next flusher
+                 * the new first flusher and arm cwqs.
+                 */
+                BUG_ON(wq->flush_color == wq->work_color);
+                BUG_ON(wq->flush_color != next->flush_color);
+
+                list_del_init(&next->list);
+                wq->first_flusher = next;
+
+                if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1))
+                        break;
+
+                /*
+                 * Meh... this color is already done, clear first
+                 * flusher and repeat cascading.
+                 */
+                wq->first_flusher = NULL;
+        }
+
+out_unlock:
+        mutex_unlock(&wq->flush_mutex);
 }
 EXPORT_SYMBOL_GPL(flush_workqueue);
 
@@ -562,43 +2304,46 @@ EXPORT_SYMBOL_GPL(flush_workqueue);
  */
 int flush_work(struct work_struct *work)
 {
+        struct worker *worker = NULL;
+        struct global_cwq *gcwq;
         struct cpu_workqueue_struct *cwq;
-        struct list_head *prev;
         struct wq_barrier barr;
 
         might_sleep();
-        cwq = get_wq_data(work);
-        if (!cwq)
+        gcwq = get_work_gcwq(work);
+        if (!gcwq)
                 return 0;
 
-        lock_map_acquire(&cwq->wq->lockdep_map);
-        lock_map_release(&cwq->wq->lockdep_map);
-
-        prev = NULL;
-        spin_lock_irq(&cwq->lock);
+        spin_lock_irq(&gcwq->lock);
         if (!list_empty(&work->entry)) {
                 /*
                  * See the comment near try_to_grab_pending()->smp_rmb().
-                 * If it was re-queued under us we are not going to wait.
+                 * If it was re-queued to a different gcwq under us, we
+                 * are not going to wait.
                  */
                 smp_rmb();
-                if (unlikely(cwq != get_wq_data(work)))
-                        goto out;
-                prev = &work->entry;
+                cwq = get_work_cwq(work);
+                if (unlikely(!cwq || gcwq != cwq->gcwq))
+                        goto already_gone;
         } else {
-                if (cwq->current_work != work)
-                        goto out;
-                prev = &cwq->worklist;
+                worker = find_worker_executing_work(gcwq, work);
+                if (!worker)
+                        goto already_gone;
+                cwq = worker->current_cwq;
         }
-        insert_wq_barrier(cwq, &barr, prev->next);
-out:
-        spin_unlock_irq(&cwq->lock);
-        if (!prev)
-                return 0;
+
+        insert_wq_barrier(cwq, &barr, work, worker);
+        spin_unlock_irq(&gcwq->lock);
+
+        lock_map_acquire(&cwq->wq->lockdep_map);
+        lock_map_release(&cwq->wq->lockdep_map);
 
         wait_for_completion(&barr.done);
         destroy_work_on_stack(&barr.work);
         return 1;
+already_gone:
+        spin_unlock_irq(&gcwq->lock);
+        return 0;
 }
 EXPORT_SYMBOL_GPL(flush_work);
 
@@ -608,54 +2353,55 @@ EXPORT_SYMBOL_GPL(flush_work);
  */
 static int try_to_grab_pending(struct work_struct *work)
 {
-        struct cpu_workqueue_struct *cwq;
+        struct global_cwq *gcwq;
         int ret = -1;
 
-        if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work)))
+        if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
                 return 0;
 
         /*
          * The queueing is in progress, or it is already queued. Try to
          * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
          */
-
-        cwq = get_wq_data(work);
-        if (!cwq)
+        gcwq = get_work_gcwq(work);
+        if (!gcwq)
                 return ret;
 
-        spin_lock_irq(&cwq->lock);
+        spin_lock_irq(&gcwq->lock);
         if (!list_empty(&work->entry)) {
                 /*
-                 * This work is queued, but perhaps we locked the wrong cwq.
+                 * This work is queued, but perhaps we locked the wrong gcwq.
                  * In that case we must see the new value after rmb(), see
                  * insert_work()->wmb().
                  */
                 smp_rmb();
-                if (cwq == get_wq_data(work)) {
+                if (gcwq == get_work_gcwq(work)) {
                         debug_work_deactivate(work);
                         list_del_init(&work->entry);
+                        cwq_dec_nr_in_flight(get_work_cwq(work),
+                                             get_work_color(work));
                         ret = 1;
                 }
         }
-        spin_unlock_irq(&cwq->lock);
+        spin_unlock_irq(&gcwq->lock);
 
         return ret;
 }
 
-static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
-                                struct work_struct *work)
+static void wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work)
 {
         struct wq_barrier barr;
-        int running = 0;
+        struct worker *worker;
 
-        spin_lock_irq(&cwq->lock);
-        if (unlikely(cwq->current_work == work)) {
-                insert_wq_barrier(cwq, &barr, cwq->worklist.next);
-                running = 1;
-        }
-        spin_unlock_irq(&cwq->lock);
+        spin_lock_irq(&gcwq->lock);
+
+        worker = find_worker_executing_work(gcwq, work);
+        if (unlikely(worker))
+                insert_wq_barrier(worker->current_cwq, &barr, work, worker);
 
-        if (unlikely(running)) {
+        spin_unlock_irq(&gcwq->lock);
+
+        if (unlikely(worker)) {
                 wait_for_completion(&barr.done);
                 destroy_work_on_stack(&barr.work);
         }
@@ -663,9 +2409,6 @@ static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
 
 static void wait_on_work(struct work_struct *work)
 {
-        struct cpu_workqueue_struct *cwq;
-        struct workqueue_struct *wq;
-        const struct cpumask *cpu_map;
         int cpu;
 
         might_sleep();
@@ -673,15 +2416,8 @@ static void wait_on_work(struct work_struct *work)
         lock_map_acquire(&work->lockdep_map);
         lock_map_release(&work->lockdep_map);
 
-        cwq = get_wq_data(work);
-        if (!cwq)
-                return;
-
-        wq = cwq->wq;
-        cpu_map = wq_cpu_map(wq);
-
-        for_each_cpu(cpu, cpu_map)
-                wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
+        for_each_gcwq_cpu(cpu)
+                wait_on_cpu_work(get_gcwq(cpu), work);
 }
 
 static int __cancel_work_timer(struct work_struct *work,
@@ -696,7 +2432,7 @@ static int __cancel_work_timer(struct work_struct *work,
                 wait_on_work(work);
         } while (unlikely(ret < 0));
 
-        clear_wq_data(work);
+        clear_work_data(work);
         return ret;
 }
 
@@ -742,8 +2478,6 @@ int cancel_delayed_work_sync(struct delayed_work *dwork)
 }
 EXPORT_SYMBOL(cancel_delayed_work_sync);
 
-static struct workqueue_struct *keventd_wq __read_mostly;
-
 /**
  * schedule_work - put work task in global workqueue
  * @work: job to be done
@@ -757,7 +2491,7 @@ static struct workqueue_struct *keventd_wq __read_mostly;
  */
 int schedule_work(struct work_struct *work)
 {
-        return queue_work(keventd_wq, work);
+        return queue_work(system_wq, work);
 }
 EXPORT_SYMBOL(schedule_work);
 
@@ -770,7 +2504,7 @@ EXPORT_SYMBOL(schedule_work);
  */
 int schedule_work_on(int cpu, struct work_struct *work)
 {
-        return queue_work_on(cpu, keventd_wq, work);
+        return queue_work_on(cpu, system_wq, work);
 }
 EXPORT_SYMBOL(schedule_work_on);
 
@@ -785,7 +2519,7 @@ EXPORT_SYMBOL(schedule_work_on);
 int schedule_delayed_work(struct delayed_work *dwork,
                                         unsigned long delay)
 {
-        return queue_delayed_work(keventd_wq, dwork, delay);
+        return queue_delayed_work(system_wq, dwork, delay);
 }
 EXPORT_SYMBOL(schedule_delayed_work);
 
@@ -798,9 +2532,8 @@ EXPORT_SYMBOL(schedule_delayed_work);
 void flush_delayed_work(struct delayed_work *dwork)
 {
         if (del_timer_sync(&dwork->timer)) {
-                struct cpu_workqueue_struct *cwq;
-                cwq = wq_per_cpu(get_wq_data(&dwork->work)->wq, get_cpu());
-                __queue_work(cwq, &dwork->work);
+                __queue_work(get_cpu(), get_work_cwq(&dwork->work)->wq,
+                             &dwork->work);
                 put_cpu();
         }
         flush_work(&dwork->work);
@@ -819,7 +2552,7 @@ EXPORT_SYMBOL(flush_delayed_work);
 int schedule_delayed_work_on(int cpu,
                         struct delayed_work *dwork, unsigned long delay)
 {
-        return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
+        return queue_delayed_work_on(cpu, system_wq, dwork, delay);
 }
 EXPORT_SYMBOL(schedule_delayed_work_on);
 
@@ -835,7 +2568,6 @@ EXPORT_SYMBOL(schedule_delayed_work_on);
 int schedule_on_each_cpu(work_func_t func)
 {
         int cpu;
-        int orig = -1;
         struct work_struct *works;
 
         works = alloc_percpu(struct work_struct);
@@ -844,23 +2576,12 @@ int schedule_on_each_cpu(work_func_t func)
 
         get_online_cpus();
 
-        /*
-         * When running in keventd don't schedule a work item on
-         * itself.  Can just call directly because the work queue is
-         * already bound.  This also is faster.
-         */
-        if (current_is_keventd())
-                orig = raw_smp_processor_id();
-
         for_each_online_cpu(cpu) {
                 struct work_struct *work = per_cpu_ptr(works, cpu);
 
                 INIT_WORK(work, func);
-                if (cpu != orig)
-                        schedule_work_on(cpu, work);
+                schedule_work_on(cpu, work);
         }
-        if (orig >= 0)
-                func(per_cpu_ptr(works, orig));
 
         for_each_online_cpu(cpu)
                 flush_work(per_cpu_ptr(works, cpu));
@@ -896,7 +2617,7 @@ int schedule_on_each_cpu(work_func_t func)
  */
 void flush_scheduled_work(void)
 {
-        flush_workqueue(keventd_wq);
+        flush_workqueue(system_wq);
 }
 EXPORT_SYMBOL(flush_scheduled_work);
 
@@ -928,170 +2649,170 @@ EXPORT_SYMBOL_GPL(execute_in_process_context);
 
 int keventd_up(void)
 {
-        return keventd_wq != NULL;
+        return system_wq != NULL;
 }
 
-int current_is_keventd(void)
+static int alloc_cwqs(struct workqueue_struct *wq)
 {
-        struct cpu_workqueue_struct *cwq;
-        int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */
-        int ret = 0;
-
-        BUG_ON(!keventd_wq);
+        /*
+         * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS.
+         * Make sure that the alignment isn't lower than that of
+         * unsigned long long.
+         */
+        const size_t size = sizeof(struct cpu_workqueue_struct);
+        const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS,
+                                   __alignof__(unsigned long long));
+#ifdef CONFIG_SMP
+        bool percpu = !(wq->flags & WQ_UNBOUND);
+#else
+        bool percpu = false;
+#endif
 
-        cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
-        if (current == cwq->thread)
-                ret = 1;
+        if (percpu)
+                wq->cpu_wq.pcpu = __alloc_percpu(size, align);
+        else {
+                void *ptr;
 
-        return ret;
+                /*
+                 * Allocate enough room to align cwq and put an extra
+                 * pointer at the end pointing back to the originally
+                 * allocated pointer which will be used for free.
+                 */
+                ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL);
+                if (ptr) {
+                        wq->cpu_wq.single = PTR_ALIGN(ptr, align);
+                        *(void **)(wq->cpu_wq.single + 1) = ptr;
+                }
+        }
 
+        /* just in case, make sure it's actually aligned */
+        BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align));
+        return wq->cpu_wq.v ? 0 : -ENOMEM;
 }
 
-static struct cpu_workqueue_struct *
-init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
+static void free_cwqs(struct workqueue_struct *wq)
 {
-        struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
-
-        cwq->wq = wq;
-        spin_lock_init(&cwq->lock);
-        INIT_LIST_HEAD(&cwq->worklist);
-        init_waitqueue_head(&cwq->more_work);
+#ifdef CONFIG_SMP
+        bool percpu = !(wq->flags & WQ_UNBOUND);
+#else
+        bool percpu = false;
+#endif
 
-        return cwq;
+        if (percpu)
+                free_percpu(wq->cpu_wq.pcpu);
+        else if (wq->cpu_wq.single) {
+                /* the pointer to free is stored right after the cwq */
+                kfree(*(void **)(wq->cpu_wq.single + 1));
+        }
 }
 
-static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
+static int wq_clamp_max_active(int max_active, unsigned int flags,
+                               const char *name)
 {
-        struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
-        struct workqueue_struct *wq = cwq->wq;
-        const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d";
-        struct task_struct *p;
+        int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;
 
-        p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu);
-        /*
-         * Nobody can add the work_struct to this cwq,
-         *      if (caller is __create_workqueue)
-         *              nobody should see this wq
-         *      else // caller is CPU_UP_PREPARE
-         *              cpu is not on cpu_online_map
-         * so we can abort safely.
-         */
-        if (IS_ERR(p))
-                return PTR_ERR(p);
-        if (cwq->wq->rt)
-                sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
-        cwq->thread = p;
-
-        trace_workqueue_creation(cwq->thread, cpu);
+        if (max_active < 1 || max_active > lim)
+                printk(KERN_WARNING "workqueue: max_active %d requested for %s "
+                       "is out of range, clamping between %d and %d\n",
+                       max_active, name, 1, lim);
 
-        return 0;
+        return clamp_val(max_active, 1, lim);
 }
 
-static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
+struct workqueue_struct *__alloc_workqueue_key(const char *name,
+                                               unsigned int flags,
+                                               int max_active,
+                                               struct lock_class_key *key,
+                                               const char *lock_name)
 {
-        struct task_struct *p = cwq->thread;
+        struct workqueue_struct *wq;
+        unsigned int cpu;
 
-        if (p != NULL) {
-                if (cpu >= 0)
-                        kthread_bind(p, cpu);
-                wake_up_process(p);
-        }
-}
+        /*
+         * Unbound workqueues aren't concurrency managed and should be
+         * dispatched to workers immediately.
+         */
+        if (flags & WQ_UNBOUND)
+                flags |= WQ_HIGHPRI;
 
-struct workqueue_struct *__create_workqueue_key(const char *name,
-                                                int singlethread,
-                                                int freezeable,
-                                                int rt,
-                                                struct lock_class_key *key,
-                                                const char *lock_name)
-{
-        struct workqueue_struct *wq;
-        struct cpu_workqueue_struct *cwq;
-        int err = 0, cpu;
+        max_active = max_active ?: WQ_DFL_ACTIVE;
+        max_active = wq_clamp_max_active(max_active, flags, name);
 
         wq = kzalloc(sizeof(*wq), GFP_KERNEL);
         if (!wq)
-                return NULL;
+                goto err;
 
-        wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct);
-        if (!wq->cpu_wq) {
-                kfree(wq);
-                return NULL;
-        }
+        wq->flags = flags;
+        wq->saved_max_active = max_active;
+        mutex_init(&wq->flush_mutex);
+        atomic_set(&wq->nr_cwqs_to_flush, 0);
+        INIT_LIST_HEAD(&wq->flusher_queue);
+        INIT_LIST_HEAD(&wq->flusher_overflow);
 
         wq->name = name;
         lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
-        wq->singlethread = singlethread;
-        wq->freezeable = freezeable;
-        wq->rt = rt;
         INIT_LIST_HEAD(&wq->list);
 
-        if (singlethread) {
-                cwq = init_cpu_workqueue(wq, singlethread_cpu);
-                err = create_workqueue_thread(cwq, singlethread_cpu);
-                start_workqueue_thread(cwq, -1);
-        } else {
-                cpu_maps_update_begin();
-                /*
-                 * We must place this wq on list even if the code below fails.
-                 * cpu_down(cpu) can remove cpu from cpu_populated_map before
-                 * destroy_workqueue() takes the lock, in that case we leak
-                 * cwq[cpu]->thread.
-                 */
-                spin_lock(&workqueue_lock);
-                list_add(&wq->list, &workqueues);
-                spin_unlock(&workqueue_lock);
-                /*
-                 * We must initialize cwqs for each possible cpu even if we
-                 * are going to call destroy_workqueue() finally. Otherwise
-                 * cpu_up() can hit the uninitialized cwq once we drop the
-                 * lock.
-                 */
-                for_each_possible_cpu(cpu) {
-                        cwq = init_cpu_workqueue(wq, cpu);
-                        if (err || !cpu_online(cpu))
-                                continue;
-                        err = create_workqueue_thread(cwq, cpu);
-                        start_workqueue_thread(cwq, cpu);
-                }
-                cpu_maps_update_done();
+        if (alloc_cwqs(wq) < 0)
+                goto err;
+
+        for_each_cwq_cpu(cpu, wq) {
+                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                struct global_cwq *gcwq = get_gcwq(cpu);
+
+                BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK);
+                cwq->gcwq = gcwq;
+                cwq->wq = wq;
+                cwq->flush_color = -1;
+                cwq->max_active = max_active;
+                INIT_LIST_HEAD(&cwq->delayed_works);
         }
 
-        if (err) {
-                destroy_workqueue(wq);
-                wq = NULL;
+        if (flags & WQ_RESCUER) {
+                struct worker *rescuer;
+
+                if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL))
+                        goto err;
+
+                wq->rescuer = rescuer = alloc_worker();
+                if (!rescuer)
+                        goto err;
+
+                rescuer->task = kthread_create(rescuer_thread, wq, "%s", name);
+                if (IS_ERR(rescuer->task))
+                        goto err;
+
+                wq->rescuer = rescuer;
+                rescuer->task->flags |= PF_THREAD_BOUND;
+                wake_up_process(rescuer->task);
         }
-        return wq;
-}
-EXPORT_SYMBOL_GPL(__create_workqueue_key);
 
-static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
-{
         /*
-         * Our caller is either destroy_workqueue() or CPU_POST_DEAD,
-         * cpu_add_remove_lock protects cwq->thread.
+         * workqueue_lock protects global freeze state and workqueues
+         * list.  Grab it, set max_active accordingly and add the new
+         * workqueue to workqueues list.
          */
-        if (cwq->thread == NULL)
-                return;
+        spin_lock(&workqueue_lock);
 
-        lock_map_acquire(&cwq->wq->lockdep_map);
-        lock_map_release(&cwq->wq->lockdep_map);
+        if (workqueue_freezing && wq->flags & WQ_FREEZEABLE)
+                for_each_cwq_cpu(cpu, wq)
+                        get_cwq(cpu, wq)->max_active = 0;
 
-        flush_cpu_workqueue(cwq);
-        /*
-         * If the caller is CPU_POST_DEAD and cwq->worklist was not empty,
-         * a concurrent flush_workqueue() can insert a barrier after us.
-         * However, in that case run_workqueue() won't return and check
-         * kthread_should_stop() until it flushes all work_struct's.
-         * When ->worklist becomes empty it is safe to exit because no
-         * more work_structs can be queued on this cwq: flush_workqueue
-         * checks list_empty(), and a "normal" queue_work() can't use
-         * a dead CPU.
-         */
-        trace_workqueue_destruction(cwq->thread);
-        kthread_stop(cwq->thread);
-        cwq->thread = NULL;
+        list_add(&wq->list, &workqueues);
+
+        spin_unlock(&workqueue_lock);
+
+        return wq;
+err:
+        if (wq) {
+                free_cwqs(wq);
+                free_mayday_mask(wq->mayday_mask);
+                kfree(wq->rescuer);
+                kfree(wq);
+        }
+        return NULL;
 }
+EXPORT_SYMBOL_GPL(__alloc_workqueue_key);
 
 /**
  * destroy_workqueue - safely terminate a workqueue
@@ -1101,72 +2822,516 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
  */
 void destroy_workqueue(struct workqueue_struct *wq)
 {
-        const struct cpumask *cpu_map = wq_cpu_map(wq);
-        int cpu;
+        unsigned int cpu;
+
+        flush_workqueue(wq);
 
-        cpu_maps_update_begin();
+        /*
+         * wq list is used to freeze wq, remove from list after
+         * flushing is complete in case freeze races us.
+         */
         spin_lock(&workqueue_lock);
         list_del(&wq->list);
         spin_unlock(&workqueue_lock);
 
-        for_each_cpu(cpu, cpu_map)
-                cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
-        cpu_maps_update_done();
+        /* sanity check */
+        for_each_cwq_cpu(cpu, wq) {
+                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                int i;
+
+                for (i = 0; i < WORK_NR_COLORS; i++)
+                        BUG_ON(cwq->nr_in_flight[i]);
+                BUG_ON(cwq->nr_active);
+                BUG_ON(!list_empty(&cwq->delayed_works));
+        }
+
+        if (wq->flags & WQ_RESCUER) {
+                kthread_stop(wq->rescuer->task);
+                free_mayday_mask(wq->mayday_mask);
+        }
 
-        free_percpu(wq->cpu_wq);
+        free_cwqs(wq);
         kfree(wq);
 }
 EXPORT_SYMBOL_GPL(destroy_workqueue);
 
+/**
+ * workqueue_set_max_active - adjust max_active of a workqueue
+ * @wq: target workqueue
+ * @max_active: new max_active value.
+ *
+ * Set max_active of @wq to @max_active.
+ *
+ * CONTEXT:
+ * Don't call from IRQ context.
+ */
+void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
+{
+        unsigned int cpu;
+
+        max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
+
+        spin_lock(&workqueue_lock);
+
+        wq->saved_max_active = max_active;
+
+        for_each_cwq_cpu(cpu, wq) {
+                struct global_cwq *gcwq = get_gcwq(cpu);
+
+                spin_lock_irq(&gcwq->lock);
+
+                if (!(wq->flags & WQ_FREEZEABLE) ||
+                    !(gcwq->flags & GCWQ_FREEZING))
+                        get_cwq(gcwq->cpu, wq)->max_active = max_active;
+
+                spin_unlock_irq(&gcwq->lock);
+        }
+
+        spin_unlock(&workqueue_lock);
+}
+EXPORT_SYMBOL_GPL(workqueue_set_max_active);
+
+/**
+ * workqueue_congested - test whether a workqueue is congested
+ * @cpu: CPU in question
+ * @wq: target workqueue
+ *
+ * Test whether @wq's cpu workqueue for @cpu is congested.  There is
+ * no synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
+ *
+ * RETURNS:
+ * %true if congested, %false otherwise.
+ */
+bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq)
+{
+        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+        return !list_empty(&cwq->delayed_works);
+}
+EXPORT_SYMBOL_GPL(workqueue_congested);
+
+/**
+ * work_cpu - return the last known associated cpu for @work
+ * @work: the work of interest
+ *
+ * RETURNS:
+ * CPU number if @work was ever queued.  WORK_CPU_NONE otherwise.
+ */
+unsigned int work_cpu(struct work_struct *work)
+{
+        struct global_cwq *gcwq = get_work_gcwq(work);
+
+        return gcwq ? gcwq->cpu : WORK_CPU_NONE;
+}
+EXPORT_SYMBOL_GPL(work_cpu);
+
+/**
+ * work_busy - test whether a work is currently pending or running
+ * @work: the work to be tested
+ *
+ * Test whether @work is currently pending or running.  There is no
+ * synchronization around this function and the test result is
+ * unreliable and only useful as advisory hints or for debugging.
+ * Especially for reentrant wqs, the pending state might hide the
+ * running state.
+ *
+ * RETURNS:
+ * OR'd bitmask of WORK_BUSY_* bits.
+ */
+unsigned int work_busy(struct work_struct *work)
+{
+        struct global_cwq *gcwq = get_work_gcwq(work);
+        unsigned long flags;
+        unsigned int ret = 0;
+
+        if (!gcwq)
+                return false;
+
+        spin_lock_irqsave(&gcwq->lock, flags);
+
+        if (work_pending(work))
+                ret |= WORK_BUSY_PENDING;
+        if (find_worker_executing_work(gcwq, work))
+                ret |= WORK_BUSY_RUNNING;
+
+        spin_unlock_irqrestore(&gcwq->lock, flags);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(work_busy);
+
+/*
+ * CPU hotplug.
+ *
+ * There are two challenges in supporting CPU hotplug.  Firstly, there
+ * are a lot of assumptions on strong associations among work, cwq and
+ * gcwq which make migrating pending and scheduled works very
+ * difficult to implement without impacting hot paths.  Secondly,
+ * gcwqs serve mix of short, long and very long running works making
+ * blocked draining impractical.
+ *
+ * This is solved by allowing a gcwq to be detached from CPU, running
+ * it with unbound (rogue) workers and allowing it to be reattached
+ * later if the cpu comes back online.  A separate thread is created
+ * to govern a gcwq in such state and is called the trustee of the
+ * gcwq.
+ *
+ * Trustee states and their descriptions.
+ *
+ * START        Command state used on startup.  On CPU_DOWN_PREPARE, a
+ *              new trustee is started with this state.
+ *
+ * IN_CHARGE    Once started, trustee will enter this state after
+ *              assuming the manager role and making all existing
+ *              workers rogue.  DOWN_PREPARE waits for trustee to
+ *              enter this state.  After reaching IN_CHARGE, trustee
+ *              tries to execute the pending worklist until it's empty
+ *              and the state is set to BUTCHER, or the state is set
+ *              to RELEASE.
+ *
+ * BUTCHER      Command state which is set by the cpu callback after
+ *              the cpu has went down.  Once this state is set trustee
+ *              knows that there will be no new works on the worklist
+ *              and once the worklist is empty it can proceed to
+ *              killing idle workers.
+ *
+ * RELEASE      Command state which is set by the cpu callback if the
+ *              cpu down has been canceled or it has come online
+ *              again.  After recognizing this state, trustee stops
+ *              trying to drain or butcher and clears ROGUE, rebinds
+ *              all remaining workers back to the cpu and releases
+ *              manager role.
+ *
+ * DONE         Trustee will enter this state after BUTCHER or RELEASE
+ *              is complete.
+ *
+ *          trustee                 CPU                draining
+ *         took over                down               complete
+ * START -----------> IN_CHARGE -----------> BUTCHER -----------> DONE
+ *                        |                     |                  ^
+ *                        | CPU is back online  v   return workers |
+ *                         ----------------> RELEASE --------------
+ */
+
+/**
+ * trustee_wait_event_timeout - timed event wait for trustee
+ * @cond: condition to wait for
+ * @timeout: timeout in jiffies
+ *
+ * wait_event_timeout() for trustee to use.  Handles locking and
+ * checks for RELEASE request.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.  To be used by trustee.
+ *
+ * RETURNS:
+ * Positive indicating left time if @cond is satisfied, 0 if timed
+ * out, -1 if canceled.
+ */
+#define trustee_wait_event_timeout(cond, timeout) ({                    \
+        long __ret = (timeout);                                         \
+        while (!((cond) || (gcwq->trustee_state == TRUSTEE_RELEASE)) && \
+               __ret) {                                                 \
+                spin_unlock_irq(&gcwq->lock);                           \
+                __wait_event_timeout(gcwq->trustee_wait, (cond) ||      \
+                        (gcwq->trustee_state == TRUSTEE_RELEASE),       \
+                        __ret);                                         \
+                spin_lock_irq(&gcwq->lock);                             \
+        }                                                               \
+        gcwq->trustee_state == TRUSTEE_RELEASE ? -1 : (__ret);          \
+})
+
+/**
+ * trustee_wait_event - event wait for trustee
+ * @cond: condition to wait for
+ *
+ * wait_event() for trustee to use.  Automatically handles locking and
+ * checks for CANCEL request.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.  To be used by trustee.
+ *
+ * RETURNS:
+ * 0 if @cond is satisfied, -1 if canceled.
+ */
+#define trustee_wait_event(cond) ({                                     \
+        long __ret1;                                                    \
+        __ret1 = trustee_wait_event_timeout(cond, MAX_SCHEDULE_TIMEOUT);\
+        __ret1 < 0 ? -1 : 0;                                            \
+})
+
+static int __cpuinit trustee_thread(void *__gcwq)
+{
+        struct global_cwq *gcwq = __gcwq;
+        struct worker *worker;
+        struct work_struct *work;
+        struct hlist_node *pos;
+        long rc;
+        int i;
+
+        BUG_ON(gcwq->cpu != smp_processor_id());
+
+        spin_lock_irq(&gcwq->lock);
+        /*
+         * Claim the manager position and make all workers rogue.
+         * Trustee must be bound to the target cpu and can't be
+         * cancelled.
+         */
+        BUG_ON(gcwq->cpu != smp_processor_id());
+        rc = trustee_wait_event(!(gcwq->flags & GCWQ_MANAGING_WORKERS));
+        BUG_ON(rc < 0);
+
+        gcwq->flags |= GCWQ_MANAGING_WORKERS;
+
+        list_for_each_entry(worker, &gcwq->idle_list, entry)
+                worker->flags |= WORKER_ROGUE;
+
+        for_each_busy_worker(worker, i, pos, gcwq)
+                worker->flags |= WORKER_ROGUE;
+
+        /*
+         * Call schedule() so that we cross rq->lock and thus can
+         * guarantee sched callbacks see the rogue flag.  This is
+         * necessary as scheduler callbacks may be invoked from other
+         * cpus.
+         */
+        spin_unlock_irq(&gcwq->lock);
+        schedule();
+        spin_lock_irq(&gcwq->lock);
+
+        /*
+         * Sched callbacks are disabled now.  Zap nr_running.  After
+         * this, nr_running stays zero and need_more_worker() and
+         * keep_working() are always true as long as the worklist is
+         * not empty.
+         */
+        atomic_set(get_gcwq_nr_running(gcwq->cpu), 0);
+
+        spin_unlock_irq(&gcwq->lock);
+        del_timer_sync(&gcwq->idle_timer);
+        spin_lock_irq(&gcwq->lock);
+
+        /*
+         * We're now in charge.  Notify and proceed to drain.  We need
+         * to keep the gcwq running during the whole CPU down
+         * procedure as other cpu hotunplug callbacks may need to
+         * flush currently running tasks.
+         */
+        gcwq->trustee_state = TRUSTEE_IN_CHARGE;
+        wake_up_all(&gcwq->trustee_wait);
+
+        /*
+         * The original cpu is in the process of dying and may go away
+         * anytime now.  When that happens, we and all workers would
+         * be migrated to other cpus.  Try draining any left work.  We
+         * want to get it over with ASAP - spam rescuers, wake up as
+         * many idlers as necessary and create new ones till the
+         * worklist is empty.  Note that if the gcwq is frozen, there
+         * may be frozen works in freezeable cwqs.  Don't declare
+         * completion while frozen.
+         */
+        while (gcwq->nr_workers != gcwq->nr_idle ||
+               gcwq->flags & GCWQ_FREEZING ||
+               gcwq->trustee_state == TRUSTEE_IN_CHARGE) {
+                int nr_works = 0;
+
+                list_for_each_entry(work, &gcwq->worklist, entry) {
+                        send_mayday(work);
+                        nr_works++;
+                }
+
+                list_for_each_entry(worker, &gcwq->idle_list, entry) {
+                        if (!nr_works--)
+                                break;
+                        wake_up_process(worker->task);
+                }
+
+                if (need_to_create_worker(gcwq)) {
+                        spin_unlock_irq(&gcwq->lock);
+                        worker = create_worker(gcwq, false);
+                        spin_lock_irq(&gcwq->lock);
+                        if (worker) {
+                                worker->flags |= WORKER_ROGUE;
+                                start_worker(worker);
+                        }
+                }
+
+                /* give a breather */
+                if (trustee_wait_event_timeout(false, TRUSTEE_COOLDOWN) < 0)
+                        break;
+        }
+
+        /*
+         * Either all works have been scheduled and cpu is down, or
+         * cpu down has already been canceled.  Wait for and butcher
+         * all workers till we're canceled.
+         */
+        do {
+                rc = trustee_wait_event(!list_empty(&gcwq->idle_list));
+                while (!list_empty(&gcwq->idle_list))
+                        destroy_worker(list_first_entry(&gcwq->idle_list,
+                                                        struct worker, entry));
+        } while (gcwq->nr_workers && rc >= 0);
+
+        /*
+         * At this point, either draining has completed and no worker
+         * is left, or cpu down has been canceled or the cpu is being
+         * brought back up.  There shouldn't be any idle one left.
+         * Tell the remaining busy ones to rebind once it finishes the
+         * currently scheduled works by scheduling the rebind_work.
+         */
+        WARN_ON(!list_empty(&gcwq->idle_list));
+
+        for_each_busy_worker(worker, i, pos, gcwq) {
+                struct work_struct *rebind_work = &worker->rebind_work;
+
+                /*
+                 * Rebind_work may race with future cpu hotplug
+                 * operations.  Use a separate flag to mark that
+                 * rebinding is scheduled.
+                 */
+                worker->flags |= WORKER_REBIND;
+                worker->flags &= ~WORKER_ROGUE;
+
+                /* queue rebind_work, wq doesn't matter, use the default one */
+                if (test_and_set_bit(WORK_STRUCT_PENDING_BIT,
+                                     work_data_bits(rebind_work)))
+                        continue;
+
+                debug_work_activate(rebind_work);
+                insert_work(get_cwq(gcwq->cpu, system_wq), rebind_work,
+                            worker->scheduled.next,
+                            work_color_to_flags(WORK_NO_COLOR));
+        }
+
+        /* relinquish manager role */
+        gcwq->flags &= ~GCWQ_MANAGING_WORKERS;
+
+        /* notify completion */
+        gcwq->trustee = NULL;
+        gcwq->trustee_state = TRUSTEE_DONE;
+        wake_up_all(&gcwq->trustee_wait);
+        spin_unlock_irq(&gcwq->lock);
+        return 0;
+}
+
+/**
+ * wait_trustee_state - wait for trustee to enter the specified state
+ * @gcwq: gcwq the trustee of interest belongs to
+ * @state: target state to wait for
+ *
+ * Wait for the trustee to reach @state.  DONE is already matched.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * multiple times.  To be used by cpu_callback.
+ */
+static void __cpuinit wait_trustee_state(struct global_cwq *gcwq, int state)
+{
+        if (!(gcwq->trustee_state == state ||
+              gcwq->trustee_state == TRUSTEE_DONE)) {
+                spin_unlock_irq(&gcwq->lock);
+                __wait_event(gcwq->trustee_wait,
+                             gcwq->trustee_state == state ||
+                             gcwq->trustee_state == TRUSTEE_DONE);
+                spin_lock_irq(&gcwq->lock);
+        }
+}
+
 static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
                                                 unsigned long action,
                                                 void *hcpu)
 {
         unsigned int cpu = (unsigned long)hcpu;
-        struct cpu_workqueue_struct *cwq;
-        struct workqueue_struct *wq;
-        int err = 0;
+        struct global_cwq *gcwq = get_gcwq(cpu);
+        struct task_struct *new_trustee = NULL;
+        struct worker *uninitialized_var(new_worker);
+        unsigned long flags;
 
         action &= ~CPU_TASKS_FROZEN;
 
         switch (action) {
+        case CPU_DOWN_PREPARE:
+                new_trustee = kthread_create(trustee_thread, gcwq,
+                                             "workqueue_trustee/%d\n", cpu);
+                if (IS_ERR(new_trustee))
+                        return notifier_from_errno(PTR_ERR(new_trustee));
+                kthread_bind(new_trustee, cpu);
+                /* fall through */
         case CPU_UP_PREPARE:
-                cpumask_set_cpu(cpu, cpu_populated_map);
-        }
-undo:
-        list_for_each_entry(wq, &workqueues, list) {
-                cwq = per_cpu_ptr(wq->cpu_wq, cpu);
-
-                switch (action) {
-                case CPU_UP_PREPARE:
-                        err = create_workqueue_thread(cwq, cpu);
-                        if (!err)
-                                break;
-                        printk(KERN_ERR "workqueue [%s] for %i failed\n",
-                                wq->name, cpu);
-                        action = CPU_UP_CANCELED;
-                        err = -ENOMEM;
-                        goto undo;
-
-                case CPU_ONLINE:
-                        start_workqueue_thread(cwq, cpu);
-                        break;
-
-                case CPU_UP_CANCELED:
-                        start_workqueue_thread(cwq, -1);
-                case CPU_POST_DEAD:
-                        cleanup_workqueue_thread(cwq);
-                        break;
+                BUG_ON(gcwq->first_idle);
+                new_worker = create_worker(gcwq, false);
+                if (!new_worker) {
+                        if (new_trustee)
+                                kthread_stop(new_trustee);
+                        return NOTIFY_BAD;
                 }
         }
 
+        /* some are called w/ irq disabled, don't disturb irq status */
+        spin_lock_irqsave(&gcwq->lock, flags);
+
         switch (action) {
-        case CPU_UP_CANCELED:
+        case CPU_DOWN_PREPARE:
+                /* initialize trustee and tell it to acquire the gcwq */
+                BUG_ON(gcwq->trustee || gcwq->trustee_state != TRUSTEE_DONE);
+                gcwq->trustee = new_trustee;
+                gcwq->trustee_state = TRUSTEE_START;
+                wake_up_process(gcwq->trustee);
+                wait_trustee_state(gcwq, TRUSTEE_IN_CHARGE);
+                /* fall through */
+        case CPU_UP_PREPARE:
+                BUG_ON(gcwq->first_idle);
+                gcwq->first_idle = new_worker;
+                break;
+
+        case CPU_DYING:
+                /*
+                 * Before this, the trustee and all workers except for
+                 * the ones which are still executing works from
+                 * before the last CPU down must be on the cpu.  After
+                 * this, they'll all be diasporas.
+                 */
+                gcwq->flags |= GCWQ_DISASSOCIATED;
+                break;
+
         case CPU_POST_DEAD:
-                cpumask_clear_cpu(cpu, cpu_populated_map);
+                gcwq->trustee_state = TRUSTEE_BUTCHER;
+                /* fall through */
+        case CPU_UP_CANCELED:
+                destroy_worker(gcwq->first_idle);
+                gcwq->first_idle = NULL;
+                break;
+
+        case CPU_DOWN_FAILED:
+        case CPU_ONLINE:
+                gcwq->flags &= ~GCWQ_DISASSOCIATED;
+                if (gcwq->trustee_state != TRUSTEE_DONE) {
+                        gcwq->trustee_state = TRUSTEE_RELEASE;
+                        wake_up_process(gcwq->trustee);
+                        wait_trustee_state(gcwq, TRUSTEE_DONE);
+                }
+
+                /*
+                 * Trustee is done and there might be no worker left.
+                 * Put the first_idle in and request a real manager to
+                 * take a look.
+                 */
+                spin_unlock_irq(&gcwq->lock);
+                kthread_bind(gcwq->first_idle->task, cpu);
+                spin_lock_irq(&gcwq->lock);
+                gcwq->flags |= GCWQ_MANAGE_WORKERS;
+                start_worker(gcwq->first_idle);
+                gcwq->first_idle = NULL;
+                break;
         }
 
-        return notifier_from_errno(err);
+        spin_unlock_irqrestore(&gcwq->lock, flags);
+
+        return notifier_from_errno(0);
 }
 
 #ifdef CONFIG_SMP
@@ -1216,14 +3381,199 @@ long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
 EXPORT_SYMBOL_GPL(work_on_cpu);
 #endif /* CONFIG_SMP */
 
-void __init init_workqueues(void)
+#ifdef CONFIG_FREEZER
+
+/**
+ * freeze_workqueues_begin - begin freezing workqueues
+ *
+ * Start freezing workqueues.  After this function returns, all
+ * freezeable workqueues will queue new works to their frozen_works
+ * list instead of gcwq->worklist.
+ *
+ * CONTEXT:
+ * Grabs and releases workqueue_lock and gcwq->lock's.
+ */
+void freeze_workqueues_begin(void)
+{
+        unsigned int cpu;
+
+        spin_lock(&workqueue_lock);
+
+        BUG_ON(workqueue_freezing);
+        workqueue_freezing = true;
+
+        for_each_gcwq_cpu(cpu) {
+                struct global_cwq *gcwq = get_gcwq(cpu);
+                struct workqueue_struct *wq;
+
+                spin_lock_irq(&gcwq->lock);
+
+                BUG_ON(gcwq->flags & GCWQ_FREEZING);
+                gcwq->flags |= GCWQ_FREEZING;
+
+                list_for_each_entry(wq, &workqueues, list) {
+                        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+                        if (cwq && wq->flags & WQ_FREEZEABLE)
+                                cwq->max_active = 0;
+                }
+
+                spin_unlock_irq(&gcwq->lock);
+        }
+
+        spin_unlock(&workqueue_lock);
+}
+
+/**
+ * freeze_workqueues_busy - are freezeable workqueues still busy?
+ *
+ * Check whether freezing is complete.  This function must be called
+ * between freeze_workqueues_begin() and thaw_workqueues().
+ *
+ * CONTEXT:
+ * Grabs and releases workqueue_lock.
+ *
+ * RETURNS:
+ * %true if some freezeable workqueues are still busy.  %false if
+ * freezing is complete.
+ */
+bool freeze_workqueues_busy(void)
+{
+        unsigned int cpu;
+        bool busy = false;
+
+        spin_lock(&workqueue_lock);
+
+        BUG_ON(!workqueue_freezing);
+
+        for_each_gcwq_cpu(cpu) {
+                struct workqueue_struct *wq;
+                /*
+                 * nr_active is monotonically decreasing.  It's safe
+                 * to peek without lock.
+                 */
+                list_for_each_entry(wq, &workqueues, list) {
+                        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+                        if (!cwq || !(wq->flags & WQ_FREEZEABLE))
+                                continue;
+
+                        BUG_ON(cwq->nr_active < 0);
+                        if (cwq->nr_active) {
+                                busy = true;
+                                goto out_unlock;
+                        }
+                }
+        }
+out_unlock:
+        spin_unlock(&workqueue_lock);
+        return busy;
+}
+
+/**
+ * thaw_workqueues - thaw workqueues
+ *
+ * Thaw workqueues.  Normal queueing is restored and all collected
+ * frozen works are transferred to their respective gcwq worklists.
+ *
+ * CONTEXT:
+ * Grabs and releases workqueue_lock and gcwq->lock's.
+ */
+void thaw_workqueues(void)
+{
+        unsigned int cpu;
+
+        spin_lock(&workqueue_lock);
+
+        if (!workqueue_freezing)
+                goto out_unlock;
+
+        for_each_gcwq_cpu(cpu) {
+                struct global_cwq *gcwq = get_gcwq(cpu);
+                struct workqueue_struct *wq;
+
+                spin_lock_irq(&gcwq->lock);
+
+                BUG_ON(!(gcwq->flags & GCWQ_FREEZING));
+                gcwq->flags &= ~GCWQ_FREEZING;
+
+                list_for_each_entry(wq, &workqueues, list) {
+                        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+                        if (!cwq || !(wq->flags & WQ_FREEZEABLE))
+                                continue;
+
+                        /* restore max_active and repopulate worklist */
+                        cwq->max_active = wq->saved_max_active;
+
+                        while (!list_empty(&cwq->delayed_works) &&
+                               cwq->nr_active < cwq->max_active)
+                                cwq_activate_first_delayed(cwq);
+                }
+
+                wake_up_worker(gcwq);
+
+                spin_unlock_irq(&gcwq->lock);
+        }
+
+        workqueue_freezing = false;
+out_unlock:
+        spin_unlock(&workqueue_lock);
+}
+#endif /* CONFIG_FREEZER */
+
+static int __init init_workqueues(void)
 {
-        alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL);
+        unsigned int cpu;
+        int i;
+
+        hotcpu_notifier(workqueue_cpu_callback, CPU_PRI_WORKQUEUE);
+
+        /* initialize gcwqs */
+        for_each_gcwq_cpu(cpu) {
+                struct global_cwq *gcwq = get_gcwq(cpu);
+
+                spin_lock_init(&gcwq->lock);
+                INIT_LIST_HEAD(&gcwq->worklist);
+                gcwq->cpu = cpu;
+                if (cpu == WORK_CPU_UNBOUND)
+                        gcwq->flags |= GCWQ_DISASSOCIATED;
+
+                INIT_LIST_HEAD(&gcwq->idle_list);
+                for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)
+                        INIT_HLIST_HEAD(&gcwq->busy_hash[i]);
+
+                init_timer_deferrable(&gcwq->idle_timer);
+                gcwq->idle_timer.function = idle_worker_timeout;
+                gcwq->idle_timer.data = (unsigned long)gcwq;
+
+                setup_timer(&gcwq->mayday_timer, gcwq_mayday_timeout,
+                            (unsigned long)gcwq);
 
-        cpumask_copy(cpu_populated_map, cpu_online_mask);
-        singlethread_cpu = cpumask_first(cpu_possible_mask);
-        cpu_singlethread_map = cpumask_of(singlethread_cpu);
-        hotcpu_notifier(workqueue_cpu_callback, 0);
-        keventd_wq = create_workqueue("events");
-        BUG_ON(!keventd_wq);
+                ida_init(&gcwq->worker_ida);
+
+                gcwq->trustee_state = TRUSTEE_DONE;
+                init_waitqueue_head(&gcwq->trustee_wait);
+        }
+
+        /* create the initial worker */
+        for_each_online_gcwq_cpu(cpu) {
+                struct global_cwq *gcwq = get_gcwq(cpu);
+                struct worker *worker;
+
+                worker = create_worker(gcwq, true);
+                BUG_ON(!worker);
+                spin_lock_irq(&gcwq->lock);
+                start_worker(worker);
+                spin_unlock_irq(&gcwq->lock);
+        }
+
+        system_wq = alloc_workqueue("events", 0, 0);
+        system_long_wq = alloc_workqueue("events_long", 0, 0);
+        system_nrt_wq = alloc_workqueue("events_nrt", WQ_NON_REENTRANT, 0);
+        system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
+                                            WQ_UNBOUND_MAX_ACTIVE);
+        BUG_ON(!system_wq || !system_long_wq || !system_nrt_wq);
+        return 0;
 }
+early_initcall(init_workqueues);
diff --git a/kernel/workqueue_sched.h b/kernel/workqueue_sched.h
index af040babb742..2d10fc98dc79 100644
--- a/kernel/workqueue_sched.h
+++ b/kernel/workqueue_sched.h
@@ -4,13 +4,6 @@
  * Scheduler hooks for concurrency managed workqueue.  Only to be
  * included from sched.c and workqueue.c.
  */
-static inline void wq_worker_waking_up(struct task_struct *task,
-                                       unsigned int cpu)
-{
-}
-
-static inline struct task_struct *wq_worker_sleeping(struct task_struct *task,
-                                                     unsigned int cpu)
-{
-        return NULL;
-}
+void wq_worker_waking_up(struct task_struct *task, unsigned int cpu);
+struct task_struct *wq_worker_sleeping(struct task_struct *task,
+                                       unsigned int cpu);