[PATCH] dm-raid locking fix

This code was never designed to handle more than one instance of do_work()
running at once.
Signed-Off-By: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/md/dm-raid1.c

@@ -1230,7 +1230,7 @@ static int __init dm_mirror_init(void)
 	if (r)
 		return r;
 
-	_kmirrord_wq = create_workqueue("kmirrord");
+	_kmirrord_wq = create_singlethread_workqueue("kmirrord");
 	if (!_kmirrord_wq) {
 		DMERR("couldn't start kmirrord");
 		dm_dirty_log_exit();