[PATCH 3.16.y-ckt 097/118] blkcg: fix gendisk reference leak in blkg_conf_prep()

From: Luis Henriques
Date: Wed Aug 12 2015 - 05:10:15 EST

3.16.7-ckt16 -stable review patch. If anyone has any objections, please let me know.


From: Tejun Heo <tj@xxxxxxxxxx>

commit 5f6c2d2b7dbb541c1e922538c49fa04c494ae3d7 upstream.

When a blkcg configuration is targeted to a partition rather than a
whole device, blkg_conf_prep fails with -EINVAL; unfortunately, it
forgets to put the gendisk ref in that case. Fix it.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
block/blk-cgroup.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 28d227c5ca77..efc4fa54372a 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -716,8 +716,12 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
return -EINVAL;

disk = get_gendisk(MKDEV(major, minor), &part);
- if (!disk || part)
+ if (!disk)
return -EINVAL;
+ if (part) {
+ put_disk(disk);
+ return -EINVAL;
+ }

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