Merge branch 'for-3.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue fix from Tejun Heo:
 "This pull request contains a workqueue usage fix for firewire.

  For quite a long time now, workqueue only treats two work items
  identical iff both their addresses and callbacks match.  This is to
  avoid introducing false dependency through the work item being
  recycled while being executed.  This changes non-reentrancy guarantee
  for the users of PREPARE[_DELAYED]_WORK() - if the function changes,
  reentrancy isn't guaranteed against the previous instance.  Firewire
  depended on such nonreentrancy guarantee.

  This is fixed by doing the work item multiplexing from firewire proper
  while keeping the work function unchanged"

* 'for-3.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  firewire: don't use PREPARE_DELAYED_WORK

2 files changed, 28 insertions, 11 deletions

diff --git a/drivers/firewire/core-device.c b/drivers/firewire/core-device.c
index de4aa409abe2..2c6d5e118ac1 100644
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -916,7 +916,7 @@ static int lookup_existing_device(struct device *dev, void *data)
                 old->config_rom_retries = 0;
                 fw_notice(card, "rediscovered device %s\n", dev_name(dev));
 
-                PREPARE_DELAYED_WORK(&old->work, fw_device_update);
+                old->workfn = fw_device_update;
                 fw_schedule_device_work(old, 0);
 
                 if (current_node == card->root_node)
@@ -1075,7 +1075,7 @@ static void fw_device_init(struct work_struct *work)
         if (atomic_cmpxchg(&device->state,
                            FW_DEVICE_INITIALIZING,
                            FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
-                PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
+                device->workfn = fw_device_shutdown;
                 fw_schedule_device_work(device, SHUTDOWN_DELAY);
         } else {
                 fw_notice(card, "created device %s: GUID %08x%08x, S%d00\n",
@@ -1196,13 +1196,20 @@ static void fw_device_refresh(struct work_struct *work)
                   dev_name(&device->device), fw_rcode_string(ret));
  gone:
         atomic_set(&device->state, FW_DEVICE_GONE);
-        PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
+        device->workfn = fw_device_shutdown;
         fw_schedule_device_work(device, SHUTDOWN_DELAY);
  out:
         if (node_id == card->root_node->node_id)
                 fw_schedule_bm_work(card, 0);
 }
 
+static void fw_device_workfn(struct work_struct *work)
+{
+        struct fw_device *device = container_of(to_delayed_work(work),
+                                                struct fw_device, work);
+        device->workfn(work);
+}
+
 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
 {
         struct fw_device *device;
@@ -1252,7 +1259,8 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
                  * power-up after getting plugged in.  We schedule the
                  * first config rom scan half a second after bus reset.
                  */
-                INIT_DELAYED_WORK(&device->work, fw_device_init);
+                device->workfn = fw_device_init;
+                INIT_DELAYED_WORK(&device->work, fw_device_workfn);
                 fw_schedule_device_work(device, INITIAL_DELAY);
                 break;
 
@@ -1268,7 +1276,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
                 if (atomic_cmpxchg(&device->state,
                             FW_DEVICE_RUNNING,
                             FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
-                        PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
+                        device->workfn = fw_device_refresh;
                         fw_schedule_device_work(device,
                                 device->is_local ? 0 : INITIAL_DELAY);
                 }
@@ -1283,7 +1291,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
                 smp_wmb();  /* update node_id before generation */
                 device->generation = card->generation;
                 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
-                        PREPARE_DELAYED_WORK(&device->work, fw_device_update);
+                        device->workfn = fw_device_update;
                         fw_schedule_device_work(device, 0);
                 }
                 break;
@@ -1308,7 +1316,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
                 device = node->data;
                 if (atomic_xchg(&device->state,
                                 FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
-                        PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
+                        device->workfn = fw_device_shutdown;
                         fw_schedule_device_work(device,
                                 list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
                 }
diff --git a/drivers/firewire/sbp2.c b/drivers/firewire/sbp2.c
index 281029daf98c..7aef911fdc71 100644
--- a/drivers/firewire/sbp2.c
+++ b/drivers/firewire/sbp2.c
@@ -146,6 +146,7 @@ struct sbp2_logical_unit {
          */
         int generation;
         int retries;
+        work_func_t workfn;
         struct delayed_work work;
         bool has_sdev;
         bool blocked;
@@ -864,7 +865,7 @@ static void sbp2_login(struct work_struct *work)
         /* set appropriate retry limit(s) in BUSY_TIMEOUT register */
         sbp2_set_busy_timeout(lu);
 
-        PREPARE_DELAYED_WORK(&lu->work, sbp2_reconnect);
+        lu->workfn = sbp2_reconnect;
         sbp2_agent_reset(lu);
 
         /* This was a re-login. */
@@ -918,7 +919,7 @@ static void sbp2_login(struct work_struct *work)
          * If a bus reset happened, sbp2_update will have requeued
          * lu->work already.  Reset the work from reconnect to login.
          */
-        PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
+        lu->workfn = sbp2_login;
 }
 
 static void sbp2_reconnect(struct work_struct *work)
@@ -952,7 +953,7 @@ static void sbp2_reconnect(struct work_struct *work)
                     lu->retries++ >= 5) {
                         dev_err(tgt_dev(tgt), "failed to reconnect\n");
                         lu->retries = 0;
-                        PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
+                        lu->workfn = sbp2_login;
                 }
                 sbp2_queue_work(lu, DIV_ROUND_UP(HZ, 5));
 
@@ -972,6 +973,13 @@ static void sbp2_reconnect(struct work_struct *work)
         sbp2_conditionally_unblock(lu);
 }
 
+static void sbp2_lu_workfn(struct work_struct *work)
+{
+        struct sbp2_logical_unit *lu = container_of(to_delayed_work(work),
+                                                struct sbp2_logical_unit, work);
+        lu->workfn(work);
+}
+
 static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
 {
         struct sbp2_logical_unit *lu;
@@ -998,7 +1006,8 @@ static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
         lu->blocked  = false;
         ++tgt->dont_block;
         INIT_LIST_HEAD(&lu->orb_list);
-        INIT_DELAYED_WORK(&lu->work, sbp2_login);
+        lu->workfn = sbp2_login;
+        INIT_DELAYED_WORK(&lu->work, sbp2_lu_workfn);
 
         list_add_tail(&lu->link, &tgt->lu_list);
         return 0;