Add UNPLUG traces to all appropriate places

Added blk_unplug interface, allowing all invocations of unplugs to result
in a generated blktrace UNPLUG.

Signed-off-by: Alan D. Brunelle <Alan.Brunelle@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

11 files changed, 26 insertions, 27 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 3d489915fd22..3b927be03850 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1621,15 +1621,7 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
 {
         struct request_queue *q = bdi->unplug_io_data;
 
-        /*
-         * devices don't necessarily have an ->unplug_fn defined
-         */
-        if (q->unplug_fn) {
-                blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
-                                        q->rq.count[READ] + q->rq.count[WRITE]);
-
-                q->unplug_fn(q);
-        }
+        blk_unplug(q);
 }
 
 static void blk_unplug_work(struct work_struct *work)
@@ -1653,6 +1645,20 @@ static void blk_unplug_timeout(unsigned long data)
         kblockd_schedule_work(&q->unplug_work);
 }
 
+void blk_unplug(struct request_queue *q)
+{
+        /*
+         * devices don't necessarily have an ->unplug_fn defined
+         */
+        if (q->unplug_fn) {
+                blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
+                                        q->rq.count[READ] + q->rq.count[WRITE]);
+
+                q->unplug_fn(q);
+        }
+}
+EXPORT_SYMBOL(blk_unplug);
+
 /**
  * blk_start_queue - restart a previously stopped queue
  * @q:    The &struct request_queue in question
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 7c426d07a555..1b1ef3130e6e 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1207,8 +1207,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
                                         TASK_UNINTERRUPTIBLE);
                         spin_unlock_irq(&bitmap->lock);
-                        bitmap->mddev->queue
-                                ->unplug_fn(bitmap->mddev->queue);
+                        blk_unplug(bitmap->mddev->queue);
                         schedule();
                         finish_wait(&bitmap->overflow_wait, &__wait);
                         continue;
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 5a7eb650181e..e298d8d11f24 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1000,8 +1000,7 @@ void dm_table_unplug_all(struct dm_table *t)
                 struct dm_dev *dd = list_entry(d, struct dm_dev, list);
                 struct request_queue *q = bdev_get_queue(dd->bdev);
 
-                if (q->unplug_fn)
-                        q->unplug_fn(q);
+                blk_unplug(q);
         }
 }
 
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 56a11f6c127b..3dac1cfb8189 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -87,8 +87,7 @@ static void linear_unplug(struct request_queue *q)
 
         for (i=0; i < mddev->raid_disks; i++) {
                 struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
-                if (r_queue->unplug_fn)
-                        r_queue->unplug_fn(r_queue);
+                blk_unplug(r_queue);
         }
 }
 
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 808cd9549456..cef9ebd5a046 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5445,7 +5445,7 @@ void md_do_sync(mddev_t *mddev)
                  * about not overloading the IO subsystem. (things like an
                  * e2fsck being done on the RAID array should execute fast)
                  */
-                mddev->queue->unplug_fn(mddev->queue);
+                blk_unplug(mddev->queue);
                 cond_resched();
 
                 currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
@@ -5464,7 +5464,7 @@ void md_do_sync(mddev_t *mddev)
          * this also signals 'finished resyncing' to md_stop
          */
  out:
-        mddev->queue->unplug_fn(mddev->queue);
+        blk_unplug(mddev->queue);
 
         wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
 
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index b35731cceac6..eb631ebed686 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -125,8 +125,7 @@ static void unplug_slaves(mddev_t *mddev)
                         atomic_inc(&rdev->nr_pending);
                         rcu_read_unlock();
 
-                        if (r_queue->unplug_fn)
-                                r_queue->unplug_fn(r_queue);
+                        blk_unplug(r_queue);
 
                         rdev_dec_pending(rdev, mddev);
                         rcu_read_lock();
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index c111105fc2dc..f8e591708d1f 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -35,8 +35,7 @@ static void raid0_unplug(struct request_queue *q)
         for (i=0; i<mddev->raid_disks; i++) {
                 struct request_queue *r_queue = bdev_get_queue(devlist[i]->bdev);
 
-                if (r_queue->unplug_fn)
-                        r_queue->unplug_fn(r_queue);
+                blk_unplug(r_queue);
         }
 }
 
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 85478d6a9c1a..4a69c416e045 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -549,8 +549,7 @@ static void unplug_slaves(mddev_t *mddev)
                         atomic_inc(&rdev->nr_pending);
                         rcu_read_unlock();
 
-                        if (r_queue->unplug_fn)
-                                r_queue->unplug_fn(r_queue);
+                        blk_unplug(r_queue);
 
                         rdev_dec_pending(rdev, mddev);
                         rcu_read_lock();
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index fc6607acb6e4..5cdcc9386200 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -593,8 +593,7 @@ static void unplug_slaves(mddev_t *mddev)
                         atomic_inc(&rdev->nr_pending);
                         rcu_read_unlock();
 
-                        if (r_queue->unplug_fn)
-                                r_queue->unplug_fn(r_queue);
+                        blk_unplug(r_queue);
 
                         rdev_dec_pending(rdev, mddev);
                         rcu_read_lock();
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 82af3465a900..1cfc984cc7b7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3186,8 +3186,7 @@ static void unplug_slaves(mddev_t *mddev)
                         atomic_inc(&rdev->nr_pending);
                         rcu_read_unlock();
 
-                        if (r_queue->unplug_fn)
-                                r_queue->unplug_fn(r_queue);
+                        blk_unplug(r_queue);
 
                         rdev_dec_pending(rdev, mddev);
                         rcu_read_lock();
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8396db24d019..d18ee67b40f8 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -697,6 +697,7 @@ extern int blk_execute_rq(struct request_queue *, struct gendisk *,
 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
                                   struct request *, int, rq_end_io_fn *);
 extern int blk_verify_command(unsigned char *, int);
+extern void blk_unplug(struct request_queue *q);
 
 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 {