From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Sat, 11 Mar 2023 09:34:39 +0000 (+0100)
Subject: Revert "blk-cgroup: dropping parent refcount after pd_free_fn() is done"
X-Git-Tag: v6.1.17~1
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=deef2947d5f666210c3469e8b7e165c6111ae2fb;p=users%2Fdwmw2%2Flinux.git

Revert "blk-cgroup: dropping parent refcount after pd_free_fn() is done"

This reverts commit 029f1f1efa84387474b445dac4281cf95a398db8 which is
commit c7241babf0855d8a6180cd1743ff0ec34de40b4e upstream.

It is reported to cause problems, as only 2 of the 3 patch series were
applied to the stable branches.

Reported-by: Mike Cloaked <mike.cloaked@gmail.com>
Reported-by: Eric Biggers <ebiggers@kernel.org>
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sasha Levin <sashal@kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217174
Link: https://lore.kernel.org/r/ZAuPkCn49urWBN5P@sol.localdomain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 8d1b7757f1e4f..7c91d9195da8d 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -93,8 +93,6 @@ static void blkg_free_workfn(struct work_struct *work)
 		if (blkg->pd[i])
 			blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
 
-	if (blkg->parent)
-		blkg_put(blkg->parent);
 	if (blkg->q)
 		blk_put_queue(blkg->q);
 	free_percpu(blkg->iostat_cpu);
@@ -129,6 +127,8 @@ static void __blkg_release(struct rcu_head *rcu)
 
 	/* release the blkcg and parent blkg refs this blkg has been holding */
 	css_put(&blkg->blkcg->css);
+	if (blkg->parent)
+		blkg_put(blkg->parent);
 	blkg_free(blkg);
 }