Re: [PATCH 10/10] scsi: only start the request just before dispatching

[Bart Van Assche <bvanassche@xxxxxxx>]

On 10/5/20 1:41 AM, Christoph Hellwig wrote:
> This has no change in behavior, but improves the accounting a bit.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>   drivers/scsi/scsi_lib.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index f7b88d8cf975d5..f0254f913b3e3f 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1548,8 +1548,6 @@ static blk_status_t scsi_prepare_cmd(struct request *req)
>   			(struct scatterlist *)(cmd->prot_sdb + 1);
>   	}
>   
> -	blk_mq_start_request(req);
> -
>   	/*
>   	 * Special handling for passthrough commands, which don't go to the ULP
>   	 * at all:
> @@ -1649,7 +1647,6 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
>   		req->rq_flags |= RQF_DONTPREP;
>   	} else {
>   		clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
> -		blk_mq_start_request(req);
>   	}
>   
>   	cmd->flags &= SCMD_PRESERVED_FLAGS;
> @@ -1662,6 +1659,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
>   	memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
>   	cmd->scsi_done = scsi_mq_done;
>   
> +	blk_mq_start_request(req);
>   	reason = scsi_dispatch_cmd(cmd);
>   	if (reason) {
>   		scsi_set_blocked(cmd, reason);

That's a nice cleanup!

Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>