linux-kernel - [PATCH BUGFIX 2/4] block, bfq: turn put_queue into release_process_ref in __bfq_bic_change

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Date:   Sat, 21 Mar 2020 10:45:19 +0100
From:   Paolo Valente <paolo.valente@...aro.org>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        bfq-iosched@...glegroups.com, oleksandr@...alenko.name,
        rasibley@...hat.com, vkabatov@...hat.com, xzhou@...hat.com,
        jstancek@...hat.com, Paolo Valente <paolo.valente@...aro.org>,
        cki-project@...hat.com
Subject: [PATCH BUGFIX 2/4] block, bfq: turn put_queue into release_process_ref in __bfq_bic_change_cgroup

A bfq_put_queue() may be invoked in __bfq_bic_change_cgroup(). The
goal of this put is to release a process reference to a bfq_queue. But
process-reference releases may trigger also some extra operation, and,
to this goal, are handled through bfq_release_process_ref(). So, turn
the invocation of bfq_put_queue() into an invocation of
bfq_release_process_ref().

Tested-by: cki-project@...hat.com
Signed-off-by: Paolo Valente <paolo.valente@...aro.org>
---
 block/bfq-cgroup.c  | 5 +----
 block/bfq-iosched.c | 2 --
 block/bfq-iosched.h | 1 +
 3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 9d963ed518d1..72c6151ace96 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -714,10 +714,7 @@ static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd,
 
 		if (entity->sched_data != &bfqg->sched_data) {
 			bic_set_bfqq(bic, NULL, 0);
-			bfq_log_bfqq(bfqd, async_bfqq,
-				     "bic_change_group: %p %d",
-				     async_bfqq, async_bfqq->ref);
-			bfq_put_queue(async_bfqq);
+			bfq_release_process_ref(bfqd, async_bfqq);
 		}
 	}
 
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 8c436abfaf14..d9c1899cf05b 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2716,8 +2716,6 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq)
 	}
 }
 
-
-static
 void bfq_release_process_ref(struct bfq_data *bfqd, struct bfq_queue *bfqq)
 {
 	/*
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index d1233af9c684..cd224aaf9f52 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -955,6 +955,7 @@ void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 		     bool compensate, enum bfqq_expiration reason);
 void bfq_put_queue(struct bfq_queue *bfqq);
 void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
+void bfq_release_process_ref(struct bfq_data *bfqd, struct bfq_queue *bfqq);
 void bfq_schedule_dispatch(struct bfq_data *bfqd);
 void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
 
-- 
2.20.1