From f32e35bc3d542cb53a4226cca5ac803dc4dbe892 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@sandisk.com>
Date: Thu, 27 Apr 2017 10:11:19 -0700
Subject: dm rq: check blk_mq_register_dev() return value in
 dm_mq_init_request_queue()

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@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 2c96542..ba7c4c6 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -997,10 +997,14 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
 	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:
-- 
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