From: Damien Le Moal <damien.lemoal@wdc.com>
To: linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 3/7] block: Remove sysfs lock from elevator_init_rq()
Date: Fri, 23 Aug 2019 09:15:24 +0900 [thread overview]
Message-ID: <20190823001528.5673-4-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20190823001528.5673-1-damien.lemoal@wdc.com>
Since elevator_init_rq() is called before the device queue is registered
in sysfs, there is no possible conflict with elevator_switch(). Remove
the unnecessary locking of q->sysfs_lock mutex.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
block/elevator.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/block/elevator.c b/block/elevator.c
index 7fff06751633..6208ddc334ef 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -617,17 +617,12 @@ void elevator_init_mq(struct request_queue *q)
if (q->nr_hw_queues != 1)
return;
- /*
- * q->sysfs_lock must be held to provide mutual exclusion between
- * elevator_switch() and here.
- */
- mutex_lock(&q->sysfs_lock);
if (unlikely(q->elevator))
- goto out_unlock;
+ return;
e = elevator_get(q, "mq-deadline", false);
if (!e)
- goto out_unlock;
+ return;
err = blk_mq_init_sched(q, e);
if (err) {
@@ -635,9 +630,6 @@ void elevator_init_mq(struct request_queue *q)
"falling back to \"none\"\n", e->elevator_name);
elevator_put(e);
}
-
-out_unlock:
- mutex_unlock(&q->sysfs_lock);
}
--
2.21.0
next prev parent reply other threads:[~2019-08-23 0:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-23 0:15 [PATCH 0/7] Elevator cleanups and improvements Damien Le Moal
2019-08-23 0:15 ` [PATCH 1/7] block: Cleanup elevator_init_mq() use Damien Le Moal
2019-08-23 8:08 ` Johannes Thumshirn
2019-08-23 0:15 ` [PATCH 2/7] block: Change elevator_init_mq() to always succeed Damien Le Moal
2019-08-23 8:54 ` Johannes Thumshirn
2019-08-23 0:15 ` Damien Le Moal [this message]
2019-08-23 9:00 ` [PATCH 3/7] block: Remove sysfs lock from elevator_init_rq() Johannes Thumshirn
2019-08-23 20:32 ` Bart Van Assche
2019-08-23 0:15 ` [PATCH 4/7] block: Introduce elevator features Damien Le Moal
2019-08-23 11:19 ` Johannes Thumshirn
2019-08-23 0:15 ` [PATCH 5/7] block: Introduce zoned block device elevator feature Damien Le Moal
2019-08-23 11:41 ` Johannes Thumshirn
2019-08-23 0:15 ` [PATCH 6/7] block: Improve default elevator selection Damien Le Moal
2019-08-23 0:15 ` [PATCH 7/7] block: Delay default elevator initialization Damien Le Moal
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