[PATCH 5.15 186/279] blk-cgroup: fix missing put device in error path from blkg_conf_pref()

Greg Kroah-Hartman
2021-11-24T13:57:49Z

From: Yu Kuai <yukuai3@huawei.com>

[ Upstream commit 15c30104965101b8e76b24d27035569d6613a7d6 ]

If blk_queue_enter() failed due to queue is dying, the
blkdev_put_no_open() is needed because blkcg_conf_open_bdev() succeeded.

Fixes: 0c9d338c8443 ("blk-cgroup: synchronize blkg creation against policy deactivation")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20211102020705.2321858-1-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-cgroup.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index ebff1af402e5b..0eec59e4df65c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -639,7 +639,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
*/
ret = blk_queue_enter(q, 0);
if (ret)
- return ret;
+ goto fail;

rcu_read_lock();
spin_lock_irq(&q->queue_lock);
@@ -675,13 +675,13 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
new_blkg = blkg_alloc(pos, q, GFP_KERNEL);
if (unlikely(!new_blkg)) {
ret = -ENOMEM;
- goto fail;
+ goto fail_exit_queue;
}

if (radix_tree_preload(GFP_KERNEL)) {
blkg_free(new_blkg);
ret = -ENOMEM;
- goto fail;
+ goto fail_exit_queue;
}

rcu_read_lock();
@@ -721,9 +721,10 @@ fail_preloaded:
fail_unlock:
spin_unlock_irq(&q->queue_lock);
rcu_read_unlock();
+fail_exit_queue:
+ blk_queue_exit(q);
fail:
blkdev_put_no_open(bdev);
- blk_queue_exit(q);
/*
* If queue was bypassing, we should retry. Do so after a
* short msleep(). It isn't strictly necessary but queue
--
2.33.0