From: Chris Mason <clm@fb.com>
Date: Mon, 14 Nov 2022 10:19:30 -0800
Subject: blk-cgroup: properly pin the parent in blkcg_css_online
Git-commit: d7dbd43f4a828fa1d9a8614d5b0ac40aee6375fe
Patch-mainline: v6.1-rc6
References: bsc#1208105

blkcg_css_online is supposed to pin the blkcg of the parent, but
397c9f46ee4d refactored things and along the way, changed it to pin the
css instead.  This results in extra pins, and we end up leaking blkcgs
and cgroups.

Fixes: 397c9f46ee4d ("blk-cgroup: move blkcg_{pin,unpin}_online out of line")
Signed-off-by: Chris Mason <clm@fb.com>
Spotted-by: Rik van Riel <riel@surriel.com>
Cc: <stable@vger.kernel.org> # v5.19+
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/r/20221114181930.2093706-1-clm@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Michal Koutný <mkoutny@suse.com>
---
 block/blk-cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 6a5c849ee061..ed761c62ad0a 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1213,7 +1213,7 @@ static int blkcg_css_online(struct cgroup_subsys_state *css)
 	 * parent so that offline always happens towards the root.
 	 */
 	if (parent)
-		blkcg_pin_online(css);
+		blkcg_pin_online(&parent->css);
 	return 0;
 }