This is a note to let you know that I've just added the patch titled blk-cgroup: fix missing pd_online_fn() while activating policy to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: blk-cgroup-fix-missing-pd_online_fn-while-activating.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 215898832511a9459c12cddf72bacadbff9556aa Author: Yu Kuai <yukuai3@xxxxxxxxxx> Date: Tue Jan 3 19:28:33 2023 +0800 blk-cgroup: fix missing pd_online_fn() while activating policy [ Upstream commit e3ff8887e7db757360f97634e0d6f4b8e27a8c46 ] If the policy defines pd_online_fn(), it should be called after pd_init_fn(), like blkg_create(). Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> Acked-by: Tejun Heo <tj@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230103112833.2013432-1-yukuai1@xxxxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index dde8d0acfb34..cd085a0e5e4a 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -1445,6 +1445,10 @@ int blkcg_activate_policy(struct request_queue *q, list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) pol->pd_init_fn(blkg->pd[pol->plid]); + if (pol->pd_online_fn) + list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) + pol->pd_online_fn(blkg->pd[pol->plid]); + __set_bit(pol->plid, q->blkcg_pols); ret = 0;