[for-4.16 PATCH v3 1/3] block: only bdi_unregister() in del_gendisk() if !GENHD_FL_HIDDEN

Mike Snitzer
2018-01-11T02:12:54Z

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>
---
block/genhd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 96a66f671720..00620e01e043 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -725,7 +725,8 @@ 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);
--
2.15.0