[3.19-stable only] Revert "dm: fix AB-BA deadlock in __dm_destroy()"

This reverts commit e041aad2 (which is
a botched cherry-pick), to be replaced with a fixed backport.
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/md/dm.c

@@ -2544,14 +2544,14 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 	 * do not race with internal suspend.
 	 */
 	mutex_lock(&md->suspend_lock);
-	map = dm_get_live_table(md, &srcu_idx);
 	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);
-	mutex_unlock(&md->suspend_lock);
 
 	/*
 	 * Rare, but there may be I/O requests still going to complete,