From: Tejun Heo <tj@kernel.org>
Date: Wed, 22 Jul 2015 22:05:53 +0000 (-0400)
Subject: blkcg: fix gendisk reference leak in blkg_conf_prep()
X-Git-Tag: firefly_0821_release~3679^2~209
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=74f412afcff28566ef240dc2a0f0af3994201fad;p=firefly-linux-kernel-4.4.55.git

blkcg: fix gendisk reference leak in blkg_conf_prep()

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@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 1ff8e97f853a..8c4e81ac5e75 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -720,8 +720,12 @@ 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;
+	}
 
 	rcu_read_lock();
 	spin_lock_irq(disk->queue->queue_lock);