Re: [PATCHv2] scsi: core: set result when the command cannot be dispatched

[Bart Van Assche <bvanassche@acm.org>]

On Tue, 2019-04-09 at 17:02 -0700, Jaesoo Lee wrote:
> When SCSI blk-mq is enabled, there is a bug in handling errors in scsi_queue_rq.
> Specifically, the bug is not setting result field of scsi_request correctly when
> the dispatch of the command has been failed. Since the upper layer code
> including the sg_io ioctl expects to receive any error status from result field
> of scsi_request, the error is silently ignored and this could cause data
> corruptions for some applications.
> 
> Signed-off-by: Jaesoo Lee <jalee@purestorage.com>
> ---
>  drivers/scsi/scsi_lib.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 2018967..dc2550c 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1699,8 +1699,12 @@ static blk_status_t scsi_queue_rq(struct
> blk_mq_hw_ctx *hctx,
>                         ret = BLK_STS_DEV_RESOURCE;
>                 break;
>         default:
> +               if (unlikely(!scsi_device_online(sdev)))
> +                       scsi_req(req)->result = DID_NO_CONNECT << 16;
> +               else
> +                       scsi_req(req)->result = DID_ERROR << 16;
>                 /*
> -                * Make sure to release all allocated ressources when
> +                * Make sure to release all allocated resources when
>                  * we hit an error, as we will never see this command
>                  * again.
>                  */

Should "Fixes:" and "Cc: stable" tags be added to this patch?

Anyway:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>