Re: [PATCH-v2 10/17] target: Add protection SGLs to target_submit_cmd_map_sgls

[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 support to target_submit_cmd_map_sgls() for
> accepting 'sgl_prot' + 'sgl_prot_count' parameters for
> DIF protection information.
>
> Note the passed parameters are stored at se_cmd->t_prot_sg
> and se_cmd->t_prot_nents respectively.
>
> Also, update tcm_loop and vhost-scsi fabrics usage of
> target_submit_cmd_map_sgls() to take into account the
> new parameters.

I didn't see that you added protection allocation to transports that 
does not use
target_submit_cmd_map_sgls() - which happens to be iSCSI/iSER/SRP :(

Don't you think that prot SG allocation should be added also to 
target_alloc_sgl()? by then
se_cmd should contain the protection attributes and this routine can 
know if it needs to
allocate prot_sg as well. This is how I used it...

> 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/loopback/tcm_loop.c     |    2 +-
>   drivers/target/target_core_transport.c |   16 ++++++++++++++--
>   drivers/vhost/scsi.c                   |    2 +-
>   include/target/target_core_fabric.h    |    3 ++-
>   4 files changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
> index 763ee45..112b795 100644
> --- a/drivers/target/loopback/tcm_loop.c
> +++ b/drivers/target/loopback/tcm_loop.c
> @@ -217,7 +217,7 @@ static void tcm_loop_submission_work(struct work_struct *work)
>   			scsi_bufflen(sc), tcm_loop_sam_attr(sc),
>   			sc->sc_data_direction, 0,
>   			scsi_sglist(sc), scsi_sg_count(sc),
> -			sgl_bidi, sgl_bidi_count);
> +			sgl_bidi, sgl_bidi_count, NULL, 0);
>   	if (rc < 0) {
>   		set_host_byte(sc, DID_NO_CONNECT);
>   		goto out_done;
> diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
> index fa4fc04..aebe0bb 100644
> --- a/drivers/target/target_core_transport.c
> +++ b/drivers/target/target_core_transport.c
> @@ -1310,6 +1310,8 @@ transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
>    * @sgl_count: scatterlist count for unidirectional mapping
>    * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
>    * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
> + * @sgl_prot: struct scatterlist memory protection information
> + * @sgl_prot_count: scatterlist count for protection information
>    *
>    * Returns non zero to signal active I/O shutdown failure.  All other
>    * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
> @@ -1322,7 +1324,8 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess
>   		unsigned char *cdb, unsigned char *sense, u32 unpacked_lun,
>   		u32 data_length, int task_attr, int data_dir, int flags,
>   		struct scatterlist *sgl, u32 sgl_count,
> -		struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
> +		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
> +		struct scatterlist *sgl_prot, u32 sgl_prot_count)
>   {
>   	struct se_portal_group *se_tpg;
>   	sense_reason_t rc;
> @@ -1364,6 +1367,14 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess
>   		target_put_sess_cmd(se_sess, se_cmd);
>   		return 0;
>   	}
> +	/*
> +	 * Save pointers for SGLs containing protection information,
> +	 * if present.
> +	 */
> +	if (sgl_prot_count) {
> +		se_cmd->t_prot_sg = sgl_prot;
> +		se_cmd->t_prot_nents = sgl_prot_count;
> +	}
>   
>   	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
>   	if (rc != 0) {
> @@ -1406,6 +1417,7 @@ int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess
>   			return 0;
>   		}
>   	}
> +
>   	/*
>   	 * Check if we need to delay processing because of ALUA
>   	 * Active/NonOptimized primary access state..
> @@ -1445,7 +1457,7 @@ int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
>   {
>   	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
>   			unpacked_lun, data_length, task_attr, data_dir,
> -			flags, NULL, 0, NULL, 0);
> +			flags, NULL, 0, NULL, 0, NULL, 0);
>   }
>   EXPORT_SYMBOL(target_submit_cmd);
>   
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index f175629..84488a8 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -889,7 +889,7 @@ static void tcm_vhost_submission_work(struct work_struct *work)
>   			cmd->tvc_lun, cmd->tvc_exp_data_len,
>   			cmd->tvc_task_attr, cmd->tvc_data_direction,
>   			TARGET_SCF_ACK_KREF, sg_ptr, cmd->tvc_sgl_count,
> -			sg_bidi_ptr, sg_no_bidi);
> +			sg_bidi_ptr, sg_no_bidi, NULL, 0);
>   	if (rc < 0) {
>   		transport_send_check_condition_and_sense(se_cmd,
>   				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
> diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
> index 4cf4fda..0218d68 100644
> --- a/include/target/target_core_fabric.h
> +++ b/include/target/target_core_fabric.h
> @@ -105,7 +105,8 @@ sense_reason_t transport_lookup_cmd_lun(struct se_cmd *, u32);
>   sense_reason_t target_setup_cmd_from_cdb(struct se_cmd *, unsigned char *);
>   int	target_submit_cmd_map_sgls(struct se_cmd *, struct se_session *,
>   		unsigned char *, unsigned char *, u32, u32, int, int, int,
> -		struct scatterlist *, u32, struct scatterlist *, u32);
> +		struct scatterlist *, u32, struct scatterlist *, u32,
> +		struct scatterlist *, u32);
>   int	target_submit_cmd(struct se_cmd *, struct se_session *, unsigned char *,
>   		unsigned char *, u32, u32, int, int, int);
>   int	target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,