From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch updates transport_generic_complete_ok() and transport_generic_write_pending()
code to check for the existence of SCF_PASSTHROUGH_CONTIG_TO_SG for se_cmd I/O
descriptors of type SCF_SCSI_CONTROL_NONSG_IO_CDB that have been setup using
transport_generic_map_mem_to_cmd().
This is special case handling for TCM_Loop and other HW fabric modules that only speak
pre-registered SGL memory with se_cmd descriptors of type SCF_SCSI_CONTROL_NONSG_IO_CDB,
and that require a copy using transport_generic_[write,read]_contig() to/from the
contigious buffer at T_TASK(cmd)->t_task_buf. This is following current ordering
convention and does the special check + copy immediately preceeding the TFO->write_pending()
and TFO->queue_data_in() calls back out to fabric module code.
This patch also adds a few parameter naming+type cleanups + docbook comments for
transport_generic_map_mem_to_cmd() and drops the internal SCF_PASSTHROUGH_CONTIG_TO_SG
handling from TCM_Loop code.
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_transport.c | 67 ++++++++++++++++++++++------
drivers/target/tcm_loop/tcm_loop_fabric.c | 21 ---------
include/target/target_core_base.h | 7 +++-
include/target/target_core_transport.h | 4 +-
4 files changed, 60 insertions(+), 39 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index fda11e9..63dbb3e 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -5680,6 +5680,16 @@ void transport_generic_complete_ok(struct se_cmd *cmd)
cmd->data_length;
}
spin_unlock(&cmd->se_lun->lun_sep_lock);
+ /*
+ * If enabled by TCM fabirc module pre-registered SGL
+ * memory, perform the memcpy() from the TCM internal
+ * contigious buffer back to the original SGL.
+ */
+ if (cmd->se_cmd_flags & SCF_PASSTHROUGH_CONTIG_TO_SG)
+ transport_memcpy_write_contig(cmd,
+ T_TASK(cmd)->t_task_pt_sgl,
+ T_TASK(cmd)->t_task_buf);
+
CMD_TFO(cmd)->queue_data_in(cmd);
break;
case DMA_TO_DEVICE:
@@ -5927,31 +5937,42 @@ release_cmd:
return 0;
}
+/*
+ * transport_generic_map_mem_to_cmd - Perform SGL -> struct se_mem map
+ * @cmd: Associated se_cmd descriptor
+ * @mem: SGL style memory for TCM WRITE / READ
+ * @sg_mem_num: Number of SGL elements
+ * @mem_bidi_in: SGL style memory for TCM BIDI READ
+ * @sg_mem_bidi_num: Number of BIDI READ SGL elements
+ *
+ * Return: nonzero return cmd was rejected for -ENOMEM or inproper usage
+ * of parameters.
+ */
int transport_generic_map_mem_to_cmd(
struct se_cmd *cmd,
- void *mem,
- u32 se_mem_num,
- void *mem_bidi_in,
- u32 se_mem_bidi_num)
+ struct scatterlist *mem,
+ u32 sg_mem_num,
+ struct scatterlist *mem_bidi_in,
+ u32 sg_mem_bidi_num)
{
u32 se_mem_cnt_out = 0;
int ret;
- if (!(mem) || !(se_mem_num))
+ if (!(mem) || !(sg_mem_num))
return 0;
/*
* Passed *mem will contain a list_head containing preformatted
* struct se_mem elements...
*/
if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM)) {
- if ((mem_bidi_in) || (se_mem_bidi_num)) {
+ if ((mem_bidi_in) || (sg_mem_bidi_num)) {
printk(KERN_ERR "SCF_CMD_PASSTHROUGH_NOALLOC not supported"
" with BIDI-COMMAND\n");
return -ENOSYS;
}
T_TASK(cmd)->t_mem_list = (struct list_head *)mem;
- T_TASK(cmd)->t_tasks_se_num = se_mem_num;
+ T_TASK(cmd)->t_tasks_se_num = sg_mem_num;
cmd->se_cmd_flags |= SCF_CMD_PASSTHROUGH_NOALLOC;
return 0;
}
@@ -5979,7 +6000,7 @@ int transport_generic_map_mem_to_cmd(
/*
* Setup BIDI READ list of struct se_mem elements
*/
- if ((mem_bidi_in) && (se_mem_bidi_num)) {
+ if ((mem_bidi_in) && (sg_mem_bidi_num)) {
T_TASK(cmd)->t_mem_bidi_list = transport_init_se_mem_list();
if (!(T_TASK(cmd)->t_mem_bidi_list)) {
kfree(T_TASK(cmd)->t_mem_list);
@@ -6000,16 +6021,22 @@ int transport_generic_map_mem_to_cmd(
cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
} else if (cmd->se_cmd_flags & SCF_SCSI_CONTROL_NONSG_IO_CDB) {
+ if (mem_bidi_in || sg_mem_bidi_num) {
+ printk(KERN_ERR "BIDI-Commands not supported using "
+ "SCF_SCSI_CONTROL_NONSG_IO_CDB\n");
+ return -ENOSYS;
+ }
/*
- * For CDBs using a contiguous buffer, save the passed
- * struct scatterlist memory. After TCM storage object
- * processing has completed for this struct se_cmd, the calling
- * TCM fabric module is expected to call
- * transport_memcpy_write_contig() to copy the TCM buffer
- * back into the passed *mem of type struct scatterlist array.
+ * For incoming CDBs using a contiguous buffer internall with TCM,
+ * save the passed struct scatterlist memory. After TCM storage object
+ * processing has completed for this struct se_cmd, TCM core will call
+ * transport_memcpy_[write,read]_contig() as necessary from
+ * transport_generic_complete_ok() and transport_write_pending() in order
+ * to copy the TCM buffer to/from the original passed *mem in SGL ->
+ * struct scatterlist format.
*/
cmd->se_cmd_flags |= SCF_PASSTHROUGH_CONTIG_TO_SG;
- T_TASK(cmd)->t_task_pt_buf = mem;
+ T_TASK(cmd)->t_task_pt_sgl = mem;
}
return 0;
@@ -7036,6 +7063,16 @@ static int transport_generic_write_pending(struct se_cmd *cmd)
cmd->t_state = TRANSPORT_WRITE_PENDING;
spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock, flags);
/*
+ * For the TCM control CDBs using a contiguous buffer, do the memcpy
+ * from the passed Linux/SCSI struct scatterlist located at
+ * T_TASK(se_cmd)->t_task_pt_buf to the contiguous buffer at
+ * T_TASK(se_cmd)->t_task_buf.
+ */
+ if (cmd->se_cmd_flags & SCF_PASSTHROUGH_CONTIG_TO_SG)
+ transport_memcpy_read_contig(cmd,
+ T_TASK(cmd)->t_task_buf,
+ T_TASK(cmd)->t_task_pt_sgl);
+ /*
* Call the fabric write_pending function here to let the
* frontend know that WRITE buffers are ready.
*/
diff --git a/drivers/target/tcm_loop/tcm_loop_fabric.c b/drivers/target/tcm_loop/tcm_loop_fabric.c
index 2ac551b..27a803f 100644
--- a/drivers/target/tcm_loop/tcm_loop_fabric.c
+++ b/drivers/target/tcm_loop/tcm_loop_fabric.c
@@ -345,19 +345,6 @@ int tcm_loop_write_pending(struct se_cmd *se_cmd)
* memory, and memory has already been mapped to struct se_cmd->t_mem_list
* format with transport_generic_map_mem_to_cmd().
*
- * For the TCM control CDBs using a contiguous buffer, do the memcpy
- * from the passed Linux/SCSI struct scatterlist located at
- * T_TASK(se_cmd)->t_task_pt_buf to the contiguous buffer at
- * T_TASK(se_cmd)->t_task_buf.
- */
- if (se_cmd->se_cmd_flags & SCF_PASSTHROUGH_CONTIG_TO_SG) {
- TL_CDB_DEBUG("Calling transport_memcpy_read_contig()"
- " for SCF_PASSTHROUGH_CONTIG_TO_SG\n");
- transport_memcpy_read_contig(se_cmd,
- T_TASK(se_cmd)->t_task_buf,
- T_TASK(se_cmd)->t_task_pt_buf);
- }
- /*
* We now tell TCM to add this WRITE CDB directly into the TCM storage
* object execution queue.
*/
@@ -379,14 +366,6 @@ int tcm_loop_queue_data_in(struct se_cmd *se_cmd)
TL_CDB_DEBUG( "tcm_loop_queue_data_in() called for scsi_cmnd: %p"
" cdb: 0x%02x\n", sc, sc->cmnd[0]);
- if (se_cmd->se_cmd_flags & SCF_PASSTHROUGH_CONTIG_TO_SG) {
- TL_CDB_DEBUG("Calling transport_memcpy_write_contig()"
- " for SCF_PASSTHROUGH_CONTIG_TO_SG\n");
- transport_memcpy_write_contig(se_cmd,
- T_TASK(se_cmd)->t_task_pt_buf,
- T_TASK(se_cmd)->t_task_buf);
- }
-
sc->result = host_byte(DID_OK) | SAM_STAT_GOOD;
(*sc->scsi_done)(sc);
return 0;
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 8b98e72..ead2caf 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -462,7 +462,12 @@ struct se_transport_task {
struct scatterlist *t_tasks_sg_chained;
struct scatterlist t_tasks_sg_bounce;
void *t_task_buf;
- void *t_task_pt_buf;
+ /*
+ * Used for pre-registered fabric SGL passthrough WRITE and READ
+ * with the special SCF_PASSTHROUGH_CONTIG_TO_SG case for TCM_Loop
+ * and other HW target mode fabric modules.
+ */
+ struct scatterlist *t_task_pt_sgl;
struct list_head *t_mem_list;
/* Used for BIDI READ */
struct list_head *t_mem_bidi_list;
diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index 88d208e..a2e6ef9 100644
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -243,8 +243,8 @@ extern void transport_generic_complete_ok(struct se_cmd *);
extern void transport_free_dev_tasks(struct se_cmd *);
extern void transport_release_fe_cmd(struct se_cmd *);
extern int transport_generic_remove(struct se_cmd *, int, int);
-extern int transport_generic_map_mem_to_cmd(struct se_cmd *cmd, void *, u32,
- void *, u32);
+extern int transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *, u32,
+ struct scatterlist *, u32);
extern int transport_lun_wait_for_tasks(struct se_cmd *, struct se_lun *);
extern int transport_clear_lun_from_sessions(struct se_lun *);
extern int transport_check_aborted_status(struct se_cmd *, int);
--
1.5.6.5
--
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