[PATCH] md: clean out unplug and other queue function on md shutdown

The mddev and queue might be used for another array which does not set these,
so they need to be cleared.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c8c40c3..b5744b1 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3322,6 +3322,9 @@
 				set_disk_ro(disk, 0);
 			blk_queue_make_request(mddev->queue, md_fail_request);
 			mddev->pers->stop(mddev);
+			mddev->queue->merge_bvec_fn = NULL;
+			mddev->queue->unplug_fn = NULL;
+			mddev->queue->issue_flush_fn = NULL;
 			if (mddev->pers->sync_request)
 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);