1 files changed, 29 insertions, 19 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8c53b09b9a2c..e40059143272 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -54,6 +54,8 @@ static void do_deferred_remove(struct work_struct *w);
 
 static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
 
+static struct workqueue_struct *deferred_remove_workqueue;
+
 /*
  * For bio-based dm.
  * One of these is allocated per bio.
@@ -283,16 +285,24 @@ static int __init local_init(void)
 	if (r)
 		goto out_free_rq_tio_cache;
 
+	deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
+	if (!deferred_remove_workqueue) {
+		r = -ENOMEM;
+		goto out_uevent_exit;
+	}
+
 	_major = major;
 	r = register_blkdev(_major, _name);
 	if (r < 0)
-		goto out_uevent_exit;
+		goto out_free_workqueue;
 
 	if (!_major)
 		_major = r;
 
 	return 0;
 
+out_free_workqueue:
+	destroy_workqueue(deferred_remove_workqueue);
 out_uevent_exit:
 	dm_uevent_exit();
 out_free_rq_tio_cache:
@@ -306,6 +316,7 @@ out_free_io_cache:
 static void local_exit(void)
 {
 	flush_scheduled_work();
+	destroy_workqueue(deferred_remove_workqueue);
 
 	kmem_cache_destroy(_rq_tio_cache);
 	kmem_cache_destroy(_io_cache);
@@ -414,7 +425,7 @@ static void dm_blk_close(struct gendisk *disk, fmode_t mode)
 
 	if (atomic_dec_and_test(&md->open_count) &&
 	    (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
-		schedule_work(&deferred_remove_work);
+		queue_work(deferred_remove_workqueue, &deferred_remove_work);
 
 	dm_put(md);
 
@@ -2277,7 +2288,7 @@ int dm_setup_md_queue(struct mapped_device *md)
 	return 0;
 }
 
-static struct mapped_device *dm_find_md(dev_t dev)
+struct mapped_device *dm_get_md(dev_t dev)
 {
 	struct mapped_device *md;
 	unsigned minor = MINOR(dev);
@@ -2288,12 +2299,15 @@ static struct mapped_device *dm_find_md(dev_t dev)
 	spin_lock(&_minor_lock);
 
 	md = idr_find(&_minor_idr, minor);
-	if (md && (md == MINOR_ALLOCED ||
-		   (MINOR(disk_devt(dm_disk(md))) != minor) ||
-		   dm_deleting_md(md) ||
-		   test_bit(DMF_FREEING, &md->flags))) {
-		md = NULL;
-		goto out;
+	if (md) {
+		if ((md == MINOR_ALLOCED ||
+		     (MINOR(disk_devt(dm_disk(md))) != minor) ||
+		     dm_deleting_md(md) ||
+		     test_bit(DMF_FREEING, &md->flags))) {
+			md = NULL;
+			goto out;
+		}
+		dm_get(md);
 	}
 
 out:
@@ -2301,16 +2315,6 @@ out:
 
 	return md;
 }
-
-struct mapped_device *dm_get_md(dev_t dev)
-{
-	struct mapped_device *md = dm_find_md(dev);
-
-	if (md)
-		dm_get(md);
-
-	return md;
-}
 EXPORT_SYMBOL_GPL(dm_get_md);
 
 void *dm_get_mdptr(struct mapped_device *md)
@@ -2348,10 +2352,16 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 	set_bit(DMF_FREEING, &md->flags);
 	spin_unlock(&_minor_lock);
 
+	/*
+	 * Take suspend_lock so that presuspend and postsuspend methods
+	 * do not race with internal suspend.
+	 */
+	mutex_lock(&md->suspend_lock);
 	if (!dm_suspended_md(md)) {
 		dm_table_presuspend_targets(map);
 		dm_table_postsuspend_targets(map);
 	}
+	mutex_unlock(&md->suspend_lock);
 
 	/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
 	dm_put_live_table(md, srcu_idx);