Re: [PATCH] scsi: core: use blk_mq_requeue_request in __scsi_queue_insert

[Bart Van Assche <Bart.VanAssche@wdc.com>]

On Mon, 2018-02-26 at 15:58 +0800, Jianchao Wang wrote:
> In scsi core, __scsi_queue_insert should just put request back on
> the queue and retry using the same command as before. However, for
> blk-mq, scsi_mq_requeue_cmd is employed here which will unprepare
> the request. To align with the semantics of __scsi_queue_insert,
> just use blk_mq_requeue_request with kick_requeue_list == true.
> 
> Cc: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
> ---
>  drivers/scsi/scsi_lib.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index a86df9c..06d8110 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -191,7 +191,7 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
>  	 */
>  	cmd->result = 0;
>  	if (q->mq_ops) {
> -		scsi_mq_requeue_cmd(cmd);
> +		blk_mq_requeue_request(cmd->request, true);
>  		return;
>  	}
>  	spin_lock_irqsave(q->queue_lock, flags);

I think this patch will break the code in the aacraid driver that iterates
over sdev->cmd_list because commands are added to and removed from that
list in the prep / unprep code.

Bart.