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

Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx> · Sun, 19 Jan 2014 14:12:53 +0200

On 1/19/2014 4:44 AM, Nicholas A. Bellinger wrote:
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

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@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
  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,

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