From mboxrd@z Thu Jan  1 00:00:00 1970
From: edmund.nadolski@intel.com (Nadolski, Edmund)
Date: Mon, 12 Aug 2019 17:37:25 -0600
Subject: [PATCHv3] nvme: Return BLK_STS_TARGET if the DNR bit is set
In-Reply-To: <20190812075147.79598-1-hare@suse.de>
References: <20190812075147.79598-1-hare@suse.de>
Message-ID: <a8b400cf-94ef-a4a1-e196-a74e115357ea@intel.com>

On 8/12/2019 1:51 AM, Hannes Reinecke wrote:
> If the DNR bit is set we should not retry the command, even if
> the standard status evaluation indicates so.
> 
> Signed-off-by: Hannes Reinecke <hare at suse.com>
> ---
>   drivers/nvme/host/core.c | 21 +++++++++++++--------
>   1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index cc09b81fc7f4..5e1309709917 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -267,15 +267,20 @@ void nvme_complete_rq(struct request *req)
>   	if (nvme_req(req)->ctrl->kas)
>   		nvme_req(req)->ctrl->comp_seen = true;
>   
> -	if (unlikely(status != BLK_STS_OK && nvme_req_needs_retry(req))) {
> -		if ((req->cmd_flags & REQ_NVME_MPATH) &&
> -		    blk_path_error(status)) {
> -			nvme_failover_req(req);
> -			return;
> +	if (unlikely(status != BLK_STS_OK)) {
> +		if (nvme_req_needs_retry(req)) {
> +			if ((req->cmd_flags & REQ_NVME_MPATH) &&
> +			    blk_path_error(status)) {
> +				nvme_failover_req(req);
> +				return;
> +			}
> +			if (!blk_queue_dying(req->q)) {
> +				nvme_retry_req(req);
> +				return;
> +			}
>   		}
> -
> -		if (!blk_queue_dying(req->q)) {
> -			nvme_retry_req(req);
> +		if (nvme_req(req)->status & NVME_SC_DNR) {
> +			blk_mq_end_request(req, BLK_STS_TARGET);
>   			return;
>   		}
>   	}

This seems redundant, to re-check the NVME_SC_DNR here, after just 
checking it in nvme_req_needs_retry().

Ed