[PATCH 4.9 36/80] dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue()

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>

commit 23a601248958fa4142d49294352fe8d1fdf3e509 upstream.

Otherwise the request-based DM blk-mq request_queue will be put into
service without being properly exported via sysfs.

Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/md/dm-rq.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -997,10 +997,14 @@ int dm_mq_init_request_queue(struct mapp
 	dm_init_md_queue(md);
 
 	/* backfill 'mq' sysfs registration normally done in blk_register_queue */
-	blk_mq_register_dev(disk_to_dev(md->disk), q);
+	err = blk_mq_register_dev(disk_to_dev(md->disk), q);
+	if (err)
+		goto out_cleanup_queue;
 
 	return 0;
 
+out_cleanup_queue:
+	blk_cleanup_queue(q);
 out_tag_set:
 	blk_mq_free_tag_set(md->tag_set);
 out_kfree_tag_set: