Re: [PATCH-v2 03/15] target: Update SPC/SBC emulation for sess_prot_type

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

On 3/30/2015 6:28 AM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
>
> This patch updates standard INQUIRY, INQUIRY EVPD=0x86, READ_CAPACITY_16
> and control mode pages to use se_sess->sess_prot_type when determing which
> type of T10-PI related feature bits can be exposed.
>
> This is required for fabric sessions supporting T10-PI metadata to
> backend devices that don't have protection enabled.
>
> Cc: Martin Petersen <martin.petersen@oracle.com>
> Cc: Sagi Grimberg <sagig@mellanox.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Doug Gilbert <dgilbert@interlog.com>
> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
> ---
>   drivers/target/target_core_sbc.c | 13 +++++++++++--
>   drivers/target/target_core_spc.c | 14 +++++++++-----
>   2 files changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
> index 5b3564a..68373c9 100644
> --- a/drivers/target/target_core_sbc.c
> +++ b/drivers/target/target_core_sbc.c
> @@ -93,6 +93,8 @@ sbc_emulate_readcapacity_16(struct se_cmd *cmd)
>   {
>   	struct se_device *dev = cmd->se_dev;
>   	struct se_session *sess = cmd->se_sess;
> +	int pi_prot_type = dev->dev_attrib.pi_prot_type;
> +
>   	unsigned char *rbuf;
>   	unsigned char buf[32];
>   	unsigned long long blocks = dev->transport->get_blocks(dev);
> @@ -114,8 +116,15 @@ sbc_emulate_readcapacity_16(struct se_cmd *cmd)
>   	 * Set P_TYPE and PROT_EN bits for DIF support
>   	 */
>   	if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
> -		if (dev->dev_attrib.pi_prot_type)
> -			buf[12] = (dev->dev_attrib.pi_prot_type - 1) << 1 | 0x1;
> +		/*
> +		 * Only override a device's pi_prot_type if no T10-PI is
> +		 * available, and sess_prot_type has been explicitly enabled.
> +		 */
> +		if (!pi_prot_type)
> +			pi_prot_type = sess->sess_prot_type;
> +
> +		if (pi_prot_type)
> +			buf[12] = (pi_prot_type - 1) << 1 | 0x1;
>   	}
>
>   	if (dev->transport->get_lbppbe)
> diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
> index f310aac..9ec6459 100644
> --- a/drivers/target/target_core_spc.c
> +++ b/drivers/target/target_core_spc.c
> @@ -103,10 +103,12 @@ spc_emulate_inquiry_std(struct se_cmd *cmd, unsigned char *buf)
>   		buf[5] |= 0x8;
>   	/*
>   	 * Set Protection (PROTECT) bit when DIF has been enabled on the
> -	 * device, and the transport supports VERIFY + PASS.
> +	 * device, and the fabric supports VERIFY + PASS.  Also report
> +	 * PROTECT=1 if sess_prot_type has been configured to allow T10-PI
> +	 * to unprotected devices.
>   	 */
>   	if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
> -		if (dev->dev_attrib.pi_prot_type)
> +		if (dev->dev_attrib.pi_prot_type || cmd->se_sess->sess_prot_type)
>   			buf[5] |= 0x1;
>   	}
>
> @@ -480,9 +482,11 @@ spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
>   	 * only for TYPE3 protection.
>   	 */
>   	if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
> -		if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT)
> +		if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT ||
> +		    cmd->se_sess->sess_prot_type == TARGET_DIF_TYPE1_PROT)
>   			buf[4] = 0x5;
> -		else if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE3_PROT)
> +		else if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE3_PROT ||
> +			cmd->se_sess->sess_prot_type == TARGET_DIF_TYPE3_PROT)
>   			buf[4] = 0x4;
>   	}
>
> @@ -874,7 +878,7 @@ static int spc_modesense_control(struct se_cmd *cmd, u8 pc, u8 *p)
>   	 * TAG field.
>   	 */
>   	if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
> -		if (dev->dev_attrib.pi_prot_type)
> +		if (dev->dev_attrib.pi_prot_type || sess->sess_prot_type)
>   			p[5] |= 0x80;
>   	}
>
>

Reviewed-by: Sagi Grimberg <sagig@mellanox.com>