[PATCH 3/3] nvme: redirect commands on dying queue

[Chao Leng]

On 2020/8/14 23:15, Christoph Hellwig wrote:
> From: Chao Leng <lengchao at huawei.com>
> 
> If a command send through nvme-multupath failed on a dying queue, resend it
> on another path.
> 
> Signed-off-by: Chao Leng <lengchao at huawei.com>
> [hch: rebased on top of the completion refactoring]
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>   drivers/nvme/host/core.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 8d474adad721fb..271cb9bf29dcd0 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -275,13 +275,13 @@ static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
>   		return COMPLETE;
>   
>   	if (req->cmd_flags & REQ_NVME_MPATH) {
> -		if (nvme_is_path_error(status))
> +		if (nvme_is_path_error(status) || blk_queue_dying(req->q))
>   			return FAILOVER;
> +	} else {
> +		if (blk_queue_dying(req->q))
> +			return COMPLETE;
>   	}
>   
> -	if (blk_queue_dying(req->q))
> -		return COMPLETE;
> -
>   	return RETRY;
>   } 
If path related error, retry maybe fail again. So we should not retry local
for path related error. Suggest do like this:
	if (nvme_is_path_error(status) || blk_queue_dying(req->q)) {
		if (req->cmd_flags & REQ_NVME_MPATH)
			return FAILOVER;
		else
			return COMPLETE;
	}
	return RETRY;