Merge branch 'for-linus' of git://git.kernel.dk/linux-block

Pull block bits from Jens Axboe:
 "As vacation is coming up, thought I'd better get rid of my pending
  changes in my for-linus branch for this iteration.  It contains:

   - Two patches for mtip32xx.  Killing a non-compliant sysfs interface
     and moving it to debugfs, where it belongs.

   - A few patches from Asias.  Two legit bug fixes, and one killing an
     interface that is no longer in use.

   - A patch from Jan, making the annoying partition ioctl warning a bit
     less annoying, by restricting it to !CAP_SYS_RAWIO only.

   - Three bug fixes for drbd from Lars Ellenberg.

   - A fix for an old regression for umem, it hasn't really worked since
     the plugging scheme was changed in 3.0.

   - A few fixes from Tejun.

   - A splice fix from Eric Dumazet, fixing an issue with pipe
     resizing."

* 'for-linus' of git://git.kernel.dk/linux-block:
  scsi: Silence unnecessary warnings about ioctl to partition
  block: Drop dead function blk_abort_queue()
  block: Mitigate lock unbalance caused by lock switching
  block: Avoid missed wakeup in request waitqueue
  umem: fix up unplugging
  splice: fix racy pipe->buffers uses
  drbd: fix null pointer dereference with on-congestion policy when diskless
  drbd: fix list corruption by failing but already aborted reads
  drbd: fix access of unallocated pages and kernel panic
  xen/blkfront: Add WARN to deal with misbehaving backends.
  blkcg: drop local variable @q from blkg_destroy()
  mtip32xx: Create debugfs entries for troubleshooting
  mtip32xx: Remove 'registers' and 'flags' from sysfs
  blkcg: fix blkg_alloc() failure path
  block: blkcg_policy_cfq shouldn't be used if !CONFIG_CFQ_GROUP_IOSCHED
  block: fix return value on cfq_init() failure
  mtip32xx: Remove version.h header file inclusion
  xen/blkback: Copy id field when doing BLKIF_DISCARD.

20 files changed, 338 insertions, 200 deletions

diff --git a/Documentation/ABI/testing/sysfs-block-rssd b/Documentation/ABI/testing/sysfs-block-rssd
index 679ce3543122..beef30c046b0 100644
--- a/Documentation/ABI/testing/sysfs-block-rssd
+++ b/Documentation/ABI/testing/sysfs-block-rssd
@@ -1,26 +1,5 @@
-What:           /sys/block/rssd*/registers
-Date:           March 2012
-KernelVersion:  3.3
-Contact:        Asai Thambi S P <asamymuthupa@micron.com>
-Description:    This is a read-only file. Dumps below driver information and
-                hardware registers.
-                    - S ACTive
-                    - Command Issue
-                    - Completed
-                    - PORT IRQ STAT
-                    - HOST IRQ STAT
-                    - Allocated
-                    - Commands in Q
-
 What:           /sys/block/rssd*/status
 Date:           April 2012
 KernelVersion:  3.4
 Contact:        Asai Thambi S P <asamymuthupa@micron.com>
 Description:    This is a read-only file. Indicates the status of the device.
-
-What:           /sys/block/rssd*/flags
-Date:           May 2012
-KernelVersion:  3.5
-Contact:        Asai Thambi S P <asamymuthupa@micron.com>
-Description:    This is a read-only file. Dumps the flags in port and driver
-                data structure
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 02cf6335e9bd..e7dee617358e 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -125,12 +125,8 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q)
 
                 blkg->pd[i] = pd;
                 pd->blkg = blkg;
-        }
-
-        /* invoke per-policy init */
-        for (i = 0; i < BLKCG_MAX_POLS; i++) {
-                struct blkcg_policy *pol = blkcg_policy[i];
 
+                /* invoke per-policy init */
                 if (blkcg_policy_enabled(blkg->q, pol))
                         pol->pd_init_fn(blkg);
         }
@@ -245,10 +241,9 @@ EXPORT_SYMBOL_GPL(blkg_lookup_create);
 
 static void blkg_destroy(struct blkcg_gq *blkg)
 {
-        struct request_queue *q = blkg->q;
         struct blkcg *blkcg = blkg->blkcg;
 
-        lockdep_assert_held(q->queue_lock);
+        lockdep_assert_held(blkg->q->queue_lock);
         lockdep_assert_held(&blkcg->lock);
 
         /* Something wrong if we are trying to remove same group twice */
diff --git a/block/blk-core.c b/block/blk-core.c
index 3c923a7aeb56..93eb3e4f88ce 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -361,9 +361,10 @@ EXPORT_SYMBOL(blk_put_queue);
  */
 void blk_drain_queue(struct request_queue *q, bool drain_all)
 {
+        int i;
+
         while (true) {
                 bool drain = false;
-                int i;
 
                 spin_lock_irq(q->queue_lock);
 
@@ -408,6 +409,18 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
                         break;
                 msleep(10);
         }
+
+        /*
+         * With queue marked dead, any woken up waiter will fail the
+         * allocation path, so the wakeup chaining is lost and we're
+         * left with hung waiters. We need to wake up those waiters.
+         */
+        if (q->request_fn) {
+                spin_lock_irq(q->queue_lock);
+                for (i = 0; i < ARRAY_SIZE(q->rq.wait); i++)
+                        wake_up_all(&q->rq.wait[i]);
+                spin_unlock_irq(q->queue_lock);
+        }
 }
 
 /**
@@ -467,7 +480,6 @@ void blk_cleanup_queue(struct request_queue *q)
         /* mark @q DEAD, no new request or merges will be allowed afterwards */
         mutex_lock(&q->sysfs_lock);
         queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
-
         spin_lock_irq(lock);
 
         /*
@@ -485,10 +497,6 @@ void blk_cleanup_queue(struct request_queue *q)
         queue_flag_set(QUEUE_FLAG_NOMERGES, q);
         queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
         queue_flag_set(QUEUE_FLAG_DEAD, q);
-
-        if (q->queue_lock != &q->__queue_lock)
-                q->queue_lock = &q->__queue_lock;
-
         spin_unlock_irq(lock);
         mutex_unlock(&q->sysfs_lock);
 
@@ -499,6 +507,11 @@ void blk_cleanup_queue(struct request_queue *q)
         del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
         blk_sync_queue(q);
 
+        spin_lock_irq(lock);
+        if (q->queue_lock != &q->__queue_lock)
+                q->queue_lock = &q->__queue_lock;
+        spin_unlock_irq(lock);
+
         /* @q is and will stay empty, shutdown and put */
         blk_put_queue(q);
 }
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 780354888958..6e4744cbfb56 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -197,44 +197,3 @@ void blk_add_timer(struct request *req)
                 mod_timer(&q->timeout, expiry);
 }
 
-/**
- * blk_abort_queue -- Abort all request on given queue
- * @queue:      pointer to queue
- *
- */
-void blk_abort_queue(struct request_queue *q)
-{
-        unsigned long flags;
-        struct request *rq, *tmp;
-        LIST_HEAD(list);
-
-        /*
-         * Not a request based block device, nothing to abort