The code in blk-mq-debugfs.c assumes that it is working on a blk-mq
queue and is not intended to work on a blk-sq queue. Hence only
register blk-mq debugfs attributes for blk-mq queues.

Fixes: commit 9c1051aacde8 ("blk-mq: untangle debugfs and sysfs")
Signed-off-by: Bart Van Assche <redacted>
Cc: Omar Sandoval <redacted>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Ming Lei <redacted>
---
 block/blk-sysfs.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 5e7b3924996c..0494baa743a3 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c

@@ -888,10 +888,10 @@ int blk_register_queue(struct gendisk *disk)
 		goto unlock;
 	}
 
-	if (q->mq_ops)
+	if (q->mq_ops) {
 		__blk_mq_register_dev(dev, q);
-
-	blk_mq_debugfs_register(q);
+		blk_mq_debugfs_register(q);
+	}
 
 	kobject_uevent(&q->kobj, KOBJ_ADD);
 

-- 
2.12.2