Re: [PATCH v2 4/7] scsi: scsi_debug: Split resp_read_dt0()

[John Garry <john.garry@linux.dev>]

On 9/24/26 23:54, Bart Van Assche wrote:
> +/*
> + * Returns the number of bytes transferred, or -1 with *scsi_status set to a
> + * SCSI status code on failure.
> + */
> +static int __resp_read_dt0(struct scsi_cmnd *scp, struct sdeb_store_info *sip,
> +			   u64 lba, u32 num, u32 ei_lba, int *scsi_status)
> +{
> +	u8 *cmd = scp->cmnd;
> +
> +	/* DIX + T10 DIF */
> +	if (unlikely(sdebug_dix && scsi_prot_sg_count(scp))) {
> +		switch (prot_verify_read(scp, lba, num, ei_lba)) {
> +		case 1: /* Guard tag error */
> +			if (cmd[1] >> 5 != 3) { /* RDPROTECT != 3 */
> +				mk_sense_buffer(scp, ABORTED_COMMAND,
> +					LOGICAL_BLOCK_GUARD_CHECK_FAILED);
> +				*scsi_status = check_condition_result;
> +				return -1;
> +			} else if (scp->prot_flags & SCSI_PROT_GUARD_CHECK) {
> +				mk_sense_buffer(scp, ILLEGAL_REQUEST,
> +					LOGICAL_BLOCK_GUARD_CHECK_FAILED);
> +				*scsi_status = illegal_condition_result;
> +				return -1;
> +			}
> +			break;
> +		case 3: /* Reference tag error */
> +			if (cmd[1] >> 5 != 3) { /* RDPROTECT != 3 */
> +				mk_sense_buffer(scp, ABORTED_COMMAND,
> +					LOGICAL_BLOCK_REFERENCE_TAG_CHECK_FAILED);
> +				*scsi_status = check_condition_result;
> +				return -1;
> +			} else if (scp->prot_flags & SCSI_PROT_REF_CHECK) {
> +				mk_sense_buffer(scp, ILLEGAL_REQUEST,
> +					LOGICAL_BLOCK_REFERENCE_TAG_CHECK_FAILED);
> +				*scsi_status = illegal_condition_result;
> +				return -1;
> +			}
> +			break;
> +		}
> +	}
> +
> +	*scsi_status = DID_ERROR << 16;

This just seems odd. We are still setting scsi_status = DID_ERROR << 16 
even if no error. I know that it is not checked (for no error), but it 
is a good practice to make it hold a proper value.

Similar could be said how it is initialized in resp_read_dt0().
> +	return do_device_access(sip, scp, 0, lba, num, 0, false, false);
> +}