From abca8b2072779efa72ef2f45bad405c95c1eba1d Mon Sep 17 00:00:00 2001

From: Jan Kara <jack@suse.cz>

Date: Fri, 4 Mar 2022 15:35:37 +0100

Subject: [PATCH 7/9] bfq: Track whether bfq_group is still online

References: bsc#1197926

Patch-mainline: submitted, in linux-block tree

Track whether bfq_group is still online. We cannot rely on

blkcg_gq->online because that gets cleared only after all policies are

offlined and we need something that gets updated already under

bfqd->lock when we are cleaning up our bfq_group to be able to guarantee

that when we see online bfq_group, it will stay online while we are

holding bfqd->lock lock.

Cc: stable@vger.kernel.org

Tested-by: "yukuai (C)" <yukuai3@huawei.com>

Signed-off-by: Jan Kara <jack@suse.cz>

---

 block/bfq-cgroup.c  | 3 ++-

 block/bfq-iosched.h | 2 ++

 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c

index 9352f3cc2377..879380c2bc7e 100644

--- a/block/bfq-cgroup.c

+++ b/block/bfq-cgroup.c

@@ -557,6 +557,7 @@ static void bfq_pd_init(struct blkg_policy_data *pd)

 				   */

 	bfqg->bfqd = bfqd;

 	bfqg->active_entities = 0;

+	bfqg->online = true;

 	bfqg->rq_pos_tree = RB_ROOT;

 }

@@ -603,7 +604,6 @@ struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,

 	struct bfq_entity *entity;

 	bfqg = bfq_lookup_bfqg(bfqd, blkcg);

-

 	if (unlikely(!bfqg))

 		return NULL;

@@ -979,6 +979,7 @@ static void bfq_pd_offline(struct blkg_policy_data *pd)

 put_async_queues:

 	bfq_put_async_queues(bfqd, bfqg);

+	bfqg->online = false;

 	spin_unlock_irqrestore(&bfqd->lock, flags);

 	/*

diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h

index a56763045d19..4664e2f3e828 100644

--- a/block/bfq-iosched.h

+++ b/block/bfq-iosched.h

@@ -928,6 +928,8 @@ struct bfq_group {

 	/* reference counter (see comments in bfq_bic_update_cgroup) */

 	int ref;

+	/* Is bfq_group still online? */

+	bool online;

 	struct bfq_entity entity;

 	struct bfq_sched_data sched_data;

-- 

2.34.1