linux-kernel - [PATCH AUTOSEL 5.15 04/15] blk-cgroup: bypass blkcg_deactivate

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Message-ID: <20231128210843.876493-4-sashal@kernel.org>
Date:   Tue, 28 Nov 2023 16:08:25 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Ming Lei <ming.lei@...hat.com>, Jens Axboe <axboe@...nel.dk>,
        Sasha Levin <sashal@...nel.org>, tj@...nel.org,
        josef@...icpanda.com, cgroups@...r.kernel.org,
        linux-block@...r.kernel.org
Subject: [PATCH AUTOSEL 5.15 04/15] blk-cgroup: bypass blkcg_deactivate_policy after destroying

From: Ming Lei <ming.lei@...hat.com>

[ Upstream commit e63a57303599b17290cd8bc48e6f20b24289a8bc ]

blkcg_deactivate_policy() can be called after blkg_destroy_all()
returns, and it isn't necessary since blkg_destroy_all has covered
policy deactivation.

Signed-off-by: Ming Lei <ming.lei@...hat.com>
Link: https://lore.kernel.org/r/20231117023527.3188627-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 block/blk-cgroup.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 3ee4c1217b636..fd81a73708645 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -425,6 +425,7 @@ static void blkg_destroy_all(struct request_queue *q)
 {
 	struct blkcg_gq *blkg, *n;
 	int count = BLKG_DESTROY_BATCH_SIZE;
+	int i;
 
 restart:
 	spin_lock_irq(&q->queue_lock);
@@ -447,6 +448,18 @@ static void blkg_destroy_all(struct request_queue *q)
 		}
 	}
 
+	/*
+	 * Mark policy deactivated since policy offline has been done, and
+	 * the free is scheduled, so future blkcg_deactivate_policy() can
+	 * be bypassed
+	 */
+	for (i = 0; i < BLKCG_MAX_POLS; i++) {
+		struct blkcg_policy *pol = blkcg_policy[i];
+
+		if (pol)
+			__clear_bit(pol->plid, q->blkcg_pols);
+	}
+
 	q->root_blkg = NULL;
 	spin_unlock_irq(&q->queue_lock);
 }
-- 
2.42.0