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From: Bart Van Assche <bvanassche@acm.org>
To: Ming Lei <ming.lei@redhat.com>,
	linux-scsi@vger.kernel.org,
	"Martin K . Petersen" <martin.petersen@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>,
	Jens Axboe <axboe@kernel.dk>,
	"Ewan D . Milne" <emilne@redhat.com>,
	Kashyap Desai <kashyap.desai@broadcom.com>,
	Hannes Reinecke <hare@suse.de>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Long Li <longli@microsoft.com>,
	linux-block@vger.kernel.org
Subject: Re: [PATCH] scsi: core: only re-run queue in scsi_end_request() if device queue is busy
Date: Sun, 17 Nov 2019 21:30:39 -0800	[thread overview]
Message-ID: <465632fa-2519-6e44-3a3c-0f81a8e6689e@acm.org> (raw)
In-Reply-To: <20191117080818.2664-1-ming.lei@redhat.com>

On 2019-11-17 00:08, Ming Lei wrote:
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 379533ce8661..212903d5f43c 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -612,7 +612,7 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
>  	if (scsi_target(sdev)->single_lun ||
>  	    !list_empty(&sdev->host->starved_list))
>  		kblockd_schedule_work(&sdev->requeue_work);
> -	else
> +	else if (READ_ONCE(sdev->restart))
>  		blk_mq_run_hw_queues(q, true);
>  

Rerunning the hardware queues is not only necessary after
scsi_dev_queue_ready() returns false but also after .queuecommand()
returns SCSI_MLQUEUE_*_BUSY. Can this patch cause queue stalls if
.queuecommand() returns SCSI_MLQUEUE_*_BUSY?

Thanks,

Bart.

  parent reply	other threads:[~2019-11-18  5:32 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-17  8:08 [PATCH] scsi: core: only re-run queue in scsi_end_request() if device queue is busy Ming Lei
2019-11-18  0:18 ` Damien Le Moal
2019-11-18  0:47   ` Ming Lei
2019-11-18  1:10     ` Damien Le Moal
2019-11-18  2:46   ` Jens Axboe
2019-11-18  5:30 ` Bart Van Assche [this message]
2019-11-18  7:08   ` Ming Lei

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