From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , "Martin K . Petersen" , =Oleksandr Natalenko , "Luis R . Rodriguez" , Bart Van Assche , Ming Lei , Hannes Reinecke , Johannes Thumshirn Subject: [PATCH v5 6/8] scsi: Reduce suspend latency Date: Mon, 2 Oct 2017 15:52:16 -0700 Message-Id: <20171002225218.18548-7-bart.vanassche@wdc.com> In-Reply-To: <20171002225218.18548-1-bart.vanassche@wdc.com> References: <20171002225218.18548-1-bart.vanassche@wdc.com> List-ID: Avoid that it can take 200 ms too long to wait for requests to finish. Note: blk_mq_freeze_queue() uses a wait queue to wait for ongoing requests to finish. Signed-off-by: Bart Van Assche Cc: Martin K. Petersen Cc: Ming Lei Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Johannes Thumshirn --- drivers/scsi/scsi_lib.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 62f905b22821..e0bef5c9dd14 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2927,21 +2927,25 @@ static void scsi_wait_for_queuecommand(struct scsi_device *sdev) int scsi_device_quiesce(struct scsi_device *sdev) { + struct request_queue *q = sdev->request_queue; + bool freeze; int err; mutex_lock(&sdev->state_mutex); + /* + * Do not attempt to freeze the queue of an already quiesced device + * because that could result in a deadlock. + */ + freeze = sdev->sdev_state == SDEV_RUNNING; + if (freeze) + blk_mq_freeze_queue(q); err = scsi_device_set_state(sdev, SDEV_QUIESCE); mutex_unlock(&sdev->state_mutex); - if (err) - return err; + if (freeze) + blk_mq_unfreeze_queue(q); - scsi_run_queue(sdev->request_queue); - while (atomic_read(&sdev->device_busy)) { - msleep_interruptible(200); - scsi_run_queue(sdev->request_queue); - } - return 0; + return err; } EXPORT_SYMBOL(scsi_device_quiesce); -- 2.14.1