From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds support for BIDI-COMMAND passthrough into TCM Core by adding
new struct se_task->task_sg_bidi[] for the TCM/pSCSI backstore case to setup the
extra mapping for the SCSI READ payload from T_TASK(cmd)->t_mem_bidi_list.
This patch updates transport_generic_cmd_sequencer() to check for this case
with TCM/pSCSI plugin backstores and does the exntra task->task_sg_bidi[] allocation
in transport_calc_sg_num(). It also updates transport_generic_get_cdb_count()
and transport_do_se_mem_map() to handle the extra task->task_sg_bidi mapping
with a second call to transport_map_mem_to_sg().
This nice thing about this patch is that it allows TCM Core to still handle the
recieved XDWRITEREAD_* transfer length > backstore max_sectors case transparently.
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_transport.c | 105 +++++++++++++++++++++++++++----
include/target/target_core_base.h | 1 +
2 files changed, 92 insertions(+), 14 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index a20a4a9..e514ffc 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -5399,7 +5399,7 @@ static int transport_generic_cmd_sequencer(
{
struct se_device *dev = SE_DEV(cmd);
struct se_subsystem_dev *su_dev = dev->se_sub_dev;
- int ret, sector_ret = 0;
+ int ret, sector_ret = 0, passthrough;
u32 sectors = 0, size = 0, pr_reg_type = 0;
u16 service_action;
u8 alua_ascq = 0;
@@ -5587,8 +5587,15 @@ static int transport_generic_cmd_sequencer(
TCM_MAX_COMMAND_SIZE, cdb[7], service_action);
return TGCS_INVALID_CDB_FIELD;
}
+ /*
+ * Determine if this is TCM/PSCSI device and we should disable
+ * internal emulation for this CDB.
+ */
+ passthrough = (TRANSPORT(dev)->transport_type ==
+ TRANSPORT_PLUGIN_PHBA_PDEV);
+
switch (service_action) {
- case 0x0007: /* XDWRITE_READ_32 */
+ case XDWRITEREAD_32:
sectors = transport_get_sectors_32(cdb, cmd, §or_ret);
if (sector_ret)
return TGCS_UNSUPPORTED_CDB;
@@ -5602,6 +5609,11 @@ static int transport_generic_cmd_sequencer(
cmd->transport_split_cdb = &split_cdb_XX_32;
cmd->transport_get_long_lba = &transport_lba_64_ext;
/*
+ * Skip the remaining assignments for TCM/PSCSI passthrough
+ */
+ if (passthrough)
+ break;
+ /*
* Setup BIDI XOR callback to be run during
* transport_generic_complete_ok()
*/
@@ -6475,6 +6487,7 @@ void transport_free_dev_tasks(struct se_cmd *cmd)
if (!task->transport_req)
continue;
+ kfree(task->task_sg_bidi);
kfree(task->task_sg);
spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock, flags);
@@ -7056,6 +7069,7 @@ extern u32 transport_calc_sg_num(
u32 task_offset)
{
struct se_cmd *se_cmd = task->task_se_cmd;
+ struct se_device *se_dev = SE_DEV(se_cmd);
struct se_mem *se_mem = in_se_mem;
struct target_core_fabric_ops *tfo = CMD_TFO(se_cmd);
u32 sg_length, task_size = task->task_size, task_sg_num_padded;
@@ -7127,15 +7141,31 @@ next:
" task->task_sg\n");
return 0;
}
-
sg_init_table(&task->task_sg[0], task_sg_num_padded);
/*
+ * Setup task->task_sg_bidi for SCSI READ payload for
+ * TCM/pSCSI passthrough if present for BIDI-COMMAND
+ */
+ if ((T_TASK(se_cmd)->t_mem_bidi_list != NULL) &&
+ (TRANSPORT(se_dev)->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV)) {
+ task->task_sg_bidi = kzalloc(task_sg_num_padded *
+ sizeof(struct scatterlist), GFP_KERNEL);
+ if (!(task->task_sg_bidi)) {
+ printk(KERN_ERR "Unable to allocate memory for"
+ " task->task_sg_bidi\n");
+ return 0;
+ }
+ sg_init_table(&task->task_sg_bidi[0], task_sg_num_padded);
+ }
+ /*
* For the chaining case, setup the proper end of SGL for the
* initial submission struct task into struct se_subsystem_api.
* This will be cleared later by transport_do_task_sg_chain()
*/
- if (task->task_padded_sg)
+ if (task->task_padded_sg) {
sg_mark_end(&task->task_sg[task->task_sg_num - 1]);
+ sg_mark_end(&task->task_sg_bidi[task->task_sg_num - 1]);
+ }
DEBUG_SC("Successfully allocated task->task_sg_num(%u),"
" task_sg_num_padded(%u)\n", task->task_sg_num,
@@ -7485,17 +7515,34 @@ static int transport_do_se_mem_map(
return ret;
}
/*
- * Assume default that transport plugin speaks preallocated
- * scatterlists.
+ * This is the normal path for all normal non BIDI and BIDI-COMMAND
+ * WRITE payloads.. If we need to do BIDI READ passthrough for
+ * TCM/pSCSI the first call to transport_do_se_mem_map ->
+ * transport_calc_sg_num() -> transport_map_mem_to_sg() will do the
+ * allocation for task->task_sg_bidi, and the subsequent call to
+ * transport_do_se_mem_map() from transport_generic_get_cdb_count()
*/
- if (!(transport_calc_sg_num(task, in_se_mem, task_offset)))
- return -1;
- /*
- * struct se_task->task_sg now contains the struct scatterlist array.
- */
- return transport_map_mem_to_sg(task, se_mem_list, task->task_sg,
+ if (!(task->task_sg_bidi)) {
+ /*
+ * Assume default that transport plugin speaks preallocated
+ * scatterlists.
+ */
+ if (!(transport_calc_sg_num(task, in_se_mem, task_offset)))
+ return -1;
+ /*
+ * struct se_task->task_sg now contains the struct scatterlist array.
+ */
+ return transport_map_mem_to_sg(task, se_mem_list, task->task_sg,
in_se_mem, out_se_mem, se_mem_cnt,
task_offset_in);
+ }
+ /*
+ * Handle the se_mem_list -> struct task->task_sg_bidi
+ * memory map for the extra BIDI READ payload
+ */
+ return transport_map_mem_to_sg(task, se_mem_list, task->task_sg_bidi,
+ in_se_mem, out_se_mem, se_mem_cnt,
+ task_offset_in);
}
u32 transport_generic_get_cdb_count(
@@ -7509,9 +7556,10 @@ u32 transport_generic_get_cdb_count(
unsigned char *cdb = NULL;
struct se_task *task;
struct se_mem *se_mem = NULL, *se_mem_lout = NULL;
+ struct se_mem *se_mem_bidi = NULL, *se_mem_bidi_lout = NULL;
struct se_device *dev = SE_DEV(cmd);
int max_sectors_set = 0, ret;
- u32 task_offset_in = 0, se_mem_cnt = 0, task_cdbs = 0;
+ u32 task_offset_in = 0, se_mem_cnt = 0, se_mem_bidi_cnt = 0, task_cdbs = 0;
unsigned long long lba;
if (!mem_list) {
@@ -7526,6 +7574,15 @@ u32 transport_generic_get_cdb_count(
if (!(list_empty(mem_list)))
se_mem = list_entry(mem_list->next, struct se_mem, se_list);
/*
+ * Check for extra se_mem_bidi mapping for BIDI-COMMANDs to
+ * struct se_task->task_sg_bidi for TCM/pSCSI passthrough operation
+ */
+ if ((T_TASK(cmd)->t_mem_bidi_list != NULL) &&
+ !(list_empty(T_TASK(cmd)->t_mem_bidi_list)) &&
+ (TRANSPORT(dev)->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV))
+ se_mem_bidi = list_entry(T_TASK(cmd)->t_mem_bidi_list->next,
+ struct se_mem, se_list);
+ /*
* Locate the start volume segment in which the received LBA will be
* executed upon.
*/
@@ -7573,7 +7630,8 @@ u32 transport_generic_get_cdb_count(
/*
* Perform the SE OBJ plugin and/or Transport plugin specific
- * mapping for T_TASK(cmd)->t_mem_list.
+ * mapping for T_TASK(cmd)->t_mem_list. And setup the
+ * task->task_sg and if necessary task->task_sg_bidi
*/
ret = transport_do_se_mem_map(dev, task, mem_list,
NULL, se_mem, &se_mem_lout, &se_mem_cnt,
@@ -7582,6 +7640,25 @@ u32 transport_generic_get_cdb_count(
goto out;
se_mem = se_mem_lout;
+ /*
+ * Setup the T_TASK(cmd)->t_mem_bidi_list -> task->task_sg_bidi
+ * mapping for SCSI READ for BIDI-COMMAND passthrough with TCM/pSCSI
+ *
+ * Note that the first call to transport_do_se_mem_map() above will
+ * allocate struct se_task->task_sg_bidi in transport_do_se_mem_map()
+ * -> transport_calc_sg_num(), and the second here will do the
+ * mapping for SCSI READ for BIDI-COMMAND passthrough with TCM/pSCSI.
+ */
+ if (task->task_sg_bidi != NULL) {
+ ret = transport_do_se_mem_map(dev, task,
+ T_TASK(cmd)->t_mem_bidi_list, NULL,
+ se_mem_bidi, &se_mem_bidi_lout, &se_mem_bidi_cnt,
+ &task_offset_in);
+ if (ret < 0)
+ goto out;
+
+ se_mem_bidi = se_mem_bidi_lout;
+ }
task_cdbs++;
DEBUG_VOL("Incremented task_cdbs(%u) task->task_sg_num(%u)\n",
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index b68dea1..b6f3b75 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -471,6 +471,7 @@ struct se_transport_task {
struct se_task {
unsigned char task_sense;
struct scatterlist *task_sg;
+ struct scatterlist *task_sg_bidi;
void *transport_req;
u8 task_scsi_status;
u8 task_flags;
--
1.5.6.5
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