Re: [PATCH-v2 03/17] target/sbc: Add DIF setup in sbc_check_prot + sbc_parse_cdb

[Sagi Grimberg <sagig@dev.mellanox.co.il>]

On 1/19/2014 4:44 AM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
>
> This patch adds sbc_check_prot() for performing various DIF
> related CDB sanity checks, along with setting cmd->prot_type
> once sanity checks have passed.
>
> Also, add calls in sbc_parse_cdb() for READ_[10,12,16] +
> WRITE_[10,12,16] to perform DIF sanity checking.
>
> v2 changes:
>    - Make sbc_check_prot defined as static (Fengguang + Wei)
>    - Remove unprotected READ/WRITE warning (mkp)
>    - Populate cmd->prot_type + friends (Sagi)
>    - Drop SCF_PROT usage
>
> Cc: Martin K. Petersen <martin.petersen@oracle.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Sagi Grimberg <sagig@mellanox.com>
> Cc: Or Gerlitz <ogerlitz@mellanox.com>
> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
> ---
>   drivers/target/target_core_sbc.c |   62 ++++++++++++++++++++++++++++++++++++++
>   1 file changed, 62 insertions(+)
>
> diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
> index 6863dbe..91a92f3 100644
> --- a/drivers/target/target_core_sbc.c
> +++ b/drivers/target/target_core_sbc.c
> @@ -563,6 +563,44 @@ sbc_compare_and_write(struct se_cmd *cmd)
>   	return TCM_NO_SENSE;
>   }
>   
> +static bool
> +sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
> +	       u32 sectors)
> +{
> +	if (!cmd->t_prot_sg || !cmd->t_prot_nents)
> +		return true;
> +
> +	switch (dev->dev_attrib.pi_prot_type) {
> +	case TARGET_DIF_TYPE3_PROT:
> +		if (!(cdb[1] & 0xe0))
> +			return true;
> +
> +		cmd->reftag_seed = 0xffffffff;
> +		break;
> +	case TARGET_DIF_TYPE2_PROT:
> +		if (cdb[1] & 0xe0)
> +			return false;
> +
> +		cmd->reftag_seed = cmd->t_task_lba;
> +		break;
> +	case TARGET_DIF_TYPE1_PROT:
> +		if (!(cdb[1] & 0xe0))
> +			return true;
> +
> +		cmd->reftag_seed = cmd->t_task_lba;
> +		break;
> +	case TARGET_DIF_TYPE0_PROT:
> +	default:
> +		return true;
> +	}
> +
> +	cmd->prot_type = dev->dev_attrib.pi_prot_type;
> +	cmd->prot_length = dev->prot_length * sectors;
> +	cmd->prot_handover = PROT_SEPERATED;

I know that we are not planning to support interleaved mode at the 
moment, But I think
that the protection handover type is the backstore preference and should 
be taken from se_dev.
But it is not that important for now...

Sagi.