From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This v2 patch series adds BIDI-COMMAND CDB to the TCM_Loop Virtual SCSI
LLD module. This includes the following changes:
*) Add call to include/scsi/scsi_cmnd.h:scsi_bidi_cmnd() to set
TCM T_TASK(cmd)->t_task_bidi=1 in tcm_loop_allocate_core_cmd()
*) Update tcm_loop_new_cmd_map() to handle BIDI READ payload from scsi_in()
*) Drop DMA_BIDIRECTIONAL usage check from tcm_loop_queuecommand()
*) Add tcm_loop_slave_alloc() and tcm_loop_slave_configure() handlers for
struct scsi_host_template to set QUEUE_FLAG_BIDI in the former.
So far this has been tested together with commit 1f8f3eda132c using XDWRITE_READ_10
via BSG userspace code on a v2.6.36-rc3 kernel.
Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/tcm_loop/tcm_loop_fabric_scsi.c | 47 +++++++++++++++++-------
1 files changed, 34 insertions(+), 13 deletions(-)
diff --git a/drivers/target/tcm_loop/tcm_loop_fabric_scsi.c b/drivers/target/tcm_loop/tcm_loop_fabric_scsi.c
index 644f978..b95ed03 100644
--- a/drivers/target/tcm_loop/tcm_loop_fabric_scsi.c
+++ b/drivers/target/tcm_loop/tcm_loop_fabric_scsi.c
@@ -77,11 +77,11 @@ static struct se_cmd *tcm_loop_allocate_core_cmd(
printk(KERN_ERR "Unable to allocate struct tcm_loop_cmd\n");
return NULL;
}
+ se_cmd = &tl_cmd->tl_se_cmd;
/*
* Save the pointer to struct scsi_cmnd *sc
*/
tl_cmd->sc = sc;
-
/*
* Locate the SAM Task Attr from struct scsi_cmnd *
*/
@@ -100,13 +100,18 @@ static struct se_cmd *tcm_loop_allocate_core_cmd(
} else
sam_task_attr = TASK_ATTR_SIMPLE;
- se_cmd = &tl_cmd->tl_se_cmd;
/*
* Initialize struct se_cmd descriptor from target_core_mod infrastructure
*/
transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
scsi_bufflen(sc), sc->sc_data_direction, sam_task_attr,
&tl_cmd->tl_sense_buf[0]);
+
+ /*
+ * Signal BIDI usage with T_TASK(cmd)->t_tasks_bidi
+ */
+ if (scsi_bidi_cmnd(sc))
+ T_TASK(se_cmd)->t_tasks_bidi = 1;
/*
* Locate the struct se_lun pointer and attach it to struct se_cmd
*/
@@ -128,14 +133,16 @@ static struct se_cmd *tcm_loop_allocate_core_cmd(
/*
* Called by struct target_core_fabric_ops->new_cmd_map()
*
- * Always called in process context
+ * Always called in process context. A non zero return value
+ * here will signal to handle an exception based on the return code.
*/
int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
{
struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
struct tcm_loop_cmd, tl_se_cmd);
struct scsi_cmnd *sc = tl_cmd->sc;
- void *mem_ptr;
+ void *mem_ptr, *mem_bidi_ptr = NULL;
+ u32 sg_no_bidi = 0;
int ret;
/*
* Allocate the necessary tasks to complete the received CDB+data
@@ -163,6 +170,16 @@ int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
if (scsi_sg_count(sc)) {
se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM;
mem_ptr = (void *)scsi_sglist(sc);
+ /*
+ * For BIDI commands, pass in the extra READ buffer
+ * to transport_generic_map_mem_to_cmd() below..
+ */
+ if (T_TASK(se_cmd)->t_tasks_bidi) {
+ struct scsi_data_buffer *sdb = scsi_in(sc);
+
+ mem_bidi_ptr = (void *)sdb->table.sgl;
+ sg_no_bidi = sdb->table.nents;
+ }
} else {
/*
* Used for DMA_NONE
@@ -322,15 +339,6 @@ static int tcm_loop_queuecommand(
}
tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
se_tpg = &tl_tpg->tl_se_tpg;
-
- if (sc->sc_data_direction == DMA_BIDIRECTIONAL) {
- spin_lock_irq(host->host_lock);
- printk(KERN_ERR "Unsupported BIDI sc->sc_data_direction: %d\n",
- sc->sc_data_direction);
- sc->result = host_byte(DID_ERROR);
- (*done)(sc);
- return 0;
- }
/*
* Determine the SAM Task Attribute and allocate tl_cmd and
* tl_cmd->tl_se_cmd from TCM infrastructure
@@ -446,6 +454,17 @@ release:
return ret;
}
+static int tcm_loop_slave_alloc(struct scsi_device *sd)
+{
+ set_bit(QUEUE_FLAG_BIDI, &sd->request_queue->queue_flags);
+ return 0;
+}
+
+static int tcm_loop_slave_configure(struct scsi_device *sd)
+{
+ return 0;
+}
+
static struct scsi_host_template tcm_loop_driver_template = {
.proc_info = tcm_loop_proc_info,
.proc_name = "tcm_loopback",
@@ -468,6 +487,8 @@ static struct scsi_host_template tcm_loop_driver_template = {
.cmd_per_lun = TL_SCSI_CMD_PER_LUN,
.max_sectors = TL_SCSI_MAX_SECTORS,
.use_clustering = DISABLE_CLUSTERING,
+ .slave_alloc = tcm_loop_slave_alloc,
+ .slave_configure = tcm_loop_slave_configure,
.module = THIS_MODULE,
};
--
1.5.6.5
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