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Commit a026757f authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

target: Add target_submit_cmd_map_sgls for SGL fabric memory passthrough 



This patch adds a new target_submit_cmd_map_sgls() to pass pre-allocated
SGL memory using transport_generic_map_mem_to_cmd() logic into the generic
target submit I/O codepath.

It also adds a target_submit_cmd() wrapper around target_submit_cmd_map_sgls()
for existing fabric code that already assumes internal target-core SGL memory
allocation.

(v2: Rename to target_submit_cmd_map_sgls + drop TARGET_SCF_MAP_MEM flag
     in favor of non zero sgl_count check)

Reported-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 38b11bae

drivers/target/target_core_transport.c

+59 −6
Original line number Diff line number Diff line
@@ -1455,8 +1455,9 @@ int transport_handle_cdb_direct( 
}

EXPORT_SYMBOL(transport_handle_cdb_direct);



/**

 * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd

/*

 * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized

 * 			 se_cmd + use pre-allocated SGL memory.

 *

 * @se_cmd: command descriptor to submit

 * @se_sess: associated se_sess for endpoint
@@ -1467,6 +1468,10 @@ EXPORT_SYMBOL(transport_handle_cdb_direct); 
 * @task_addr: SAM task attribute

 * @data_dir: DMA data direction

 * @flags: flags for command submission from target_sc_flags_tables

 * @sgl: struct scatterlist memory for unidirectional mapping

 * @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

 *

 * Returns non zero to signal active I/O shutdown failure.  All other

 * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
@@ -1474,10 +1479,12 @@ EXPORT_SYMBOL(transport_handle_cdb_direct); 
 *

 * This may only be called from process context, and also currently

 * assumes internal allocation of fabric payload buffer by target-core.

 **/

int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,

 */

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)

		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 se_portal_group *se_tpg;

	int rc;
@@ -1524,7 +1531,21 @@ int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, 
		transport_generic_request_failure(se_cmd);

		return 0;

	}

	/*

	 * When a non zero sgl_count has been passed perform SGL passthrough

	 * mapping for pre-allocated fabric memory instead of having target

	 * core perform an internal SGL allocation..

	 */

	if (sgl_count != 0) {

		BUG_ON(!sgl);



		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,

				sgl_bidi, sgl_bidi_count);

		if (rc != 0) {

			transport_generic_request_failure(se_cmd);

			return 0;

		}

	}

	/*

	 * Check if we need to delay processing because of ALUA

	 * Active/NonOptimized primary access state..
@@ -1534,6 +1555,38 @@ int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess, 
	transport_handle_cdb_direct(se_cmd);

	return 0;

}

EXPORT_SYMBOL(target_submit_cmd_map_sgls);



/*

 * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd

 *

 * @se_cmd: command descriptor to submit

 * @se_sess: associated se_sess for endpoint

 * @cdb: pointer to SCSI CDB

 * @sense: pointer to SCSI sense buffer

 * @unpacked_lun: unpacked LUN to reference for struct se_lun

 * @data_length: fabric expected data transfer length

 * @task_addr: SAM task attribute

 * @data_dir: DMA data direction

 * @flags: flags for command submission from target_sc_flags_tables

 *

 * Returns non zero to signal active I/O shutdown failure.  All other

 * setup exceptions will be returned as a SCSI CHECK_CONDITION response,

 * but still return zero here.

 *

 * This may only be called from process context, and also currently

 * assumes internal allocation of fabric payload buffer by target-core.

 *

 * It also assumes interal target core SGL memory allocation.

 */

int target_submit_cmd(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)

{

	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);

}

EXPORT_SYMBOL(target_submit_cmd);



static void target_complete_tmr_failure(struct work_struct *work)

include/target/target_core_fabric.h

+3 −0
Original line number Diff line number Diff line
@@ -100,6 +100,9 @@ void transport_init_se_cmd(struct se_cmd *, struct target_core_fabric_ops *, 
		struct se_session *, u32, int, int, unsigned char *);

int	transport_lookup_cmd_lun(struct se_cmd *, u32);

int	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);

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,