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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: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2012-10-01 17:23:22 -07:00
parent 38b11bae6b
commit a026757ff5
2 changed files with 61 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

63
drivers/target/target_core_transport.c
View File

@ -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)

3
include/target/target_core_fabric.h
View File

@ -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,