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 1ff8e97f853ad719ee13994f0d5fc3fafb76a775..8c4e81ac5e75432c1e29917dd6bf0305505ad7a6 100644 (file)
--- 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);