From: Mike Snitzer <snitzer@redhat.com>
Date: Tue, 9 Jan 2018 20:46:49 -0500
Subject: [PATCH] block: only bdi_unregister() in del_gendisk() if
!GENHD_FL_HIDDEN
References: bsc#1077989
Git-commit: bc8d062c36e3525e81ea8237ff0ab3264c2317b6
Patch-mainline: v4.16-rc1
device_add_disk() will only call bdi_register_owner() if
!GENHD_FL_HIDDEN, so it follows that del_gendisk() should only call
bdi_unregister() if !GENHD_FL_HIDDEN.
Found with code inspection. bdi_unregister() won't do any harm if
bdi_register_owner() wasn't used but best to avoid the unnecessary
call to bdi_unregister().
Fixes: 8ddcd65325 ("block: introduce GENHD_FL_HIDDEN")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
block/genhd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/genhd.c b/block/genhd.c
index 93b5880af881..347a2dc59a07 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -714,7 +714,8 @@ void del_gendisk(struct gendisk *disk)
* Unregister bdi before releasing device numbers (as they can
* get reused and we'd get clashes in sysfs).
*/
- bdi_unregister(disk->queue->backing_dev_info);
+ if (!(disk->flags & GENHD_FL_HIDDEN))
+ bdi_unregister(disk->queue->backing_dev_info);
blk_unregister_queue(disk);
} else {
WARN_ON(1);
--
2.12.3