* [PATCH 1/2] target: Fix tfo->write_pending() fabric callback ordering
2010-12-13 23:58 [PATCH 0/2] target: Updates for HW target mode Nicholas A. Bellinger
@ 2010-12-13 23:58 ` Nicholas A. Bellinger
2010-12-13 23:58 ` [PATCH 2/2] target: Convert se_nacl->nacl_sess_lock to use spin_lock_irq() Nicholas A. Bellinger
1 sibling, 0 replies; 3+ messages in thread
From: Nicholas A. Bellinger @ 2010-12-13 23:58 UTC (permalink / raw)
To: linux-scsi, Christoph Hellwig
Cc: Mike Christie, Hannes Reinecke, FUJITA Tomonori, James Bottomley,
Nicholas Bellinger
From: Nicholas Bellinger <nab@linux-iscsi.org>
This patch moves the call to transport_cmd_check_stop() to
clear the T_TASK(cmd)->t_transport_active=0 bit before calling
back into fabric module code via CMD_TFO(cmd)->write_pending()
in order to signal that WRITE data is ready to be transfered.
This fixes the case where transport_generic_handle_data() would have
to wait until T_TASK(cmd)->t_transport_active==0 before being able
to call transport_add_cmd_to_queue(cmd, TRANSPORT_PROCESS_WRITE)
to queue the completed WRITE paylods into TCM. This allows
transport_generic_handle_data() to be called directly from interrupt
context code for HW target mode.
Note that the call to transport_cmd_check_stop() is safe with transport_off=1
preceeding CMD_TFO(cmd)->write_pending() because the se_cmd->se_lun pointer
is *not* being cleared for the write_pending case.
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
(cherry picked from commit 658efaabe00f86427761a0c79c38d757bb0e94fe)
---
drivers/target/target_core_transport.c | 31 ++++++++++++++++---------------
1 files changed, 16 insertions(+), 15 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 63fb5ca..019ccbc 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1995,18 +1995,13 @@ int transport_generic_handle_data(
struct se_cmd *cmd)
{
/*
- * Make sure that the transport has been disabled by
- * transport_write_pending() before readding this struct se_cmd to the
- * processing queue. If it has not yet been reset to zero by the
- * processing thread in transport_add_cmd_to_queue(), let other
- * processes run. If a signal was received, then we assume the
- * connection is being failed/shutdown, so we return a failure.
+ * For the software fabric case, then we assume the nexus is being
+ * failed/shutdown when signals are pending from the kthread context
+ * caller, so we return a failure. For the HW target mode case running
+ * in interrupt code, the signal_pending() check is skipped.
*/
- while (atomic_read(&T_TASK(cmd)->t_transport_active)) {
- msleep_interruptible(10);
- if (signal_pending(current))
- return -1;
- }
+ if (!in_interrupt() && signal_pending(current))
+ return -1;
/*
* If the received CDB has aleady been ABORTED by the generic
* target engine, we now call transport_check_aborted_status()
@@ -5212,16 +5207,22 @@ static int transport_generic_write_pending(struct se_cmd *cmd)
T_TASK(cmd)->t_task_buf,
T_TASK(cmd)->t_task_pt_sgl);
/*
+ * Clear the se_cmd for WRITE_PENDING status in order to set
+ * T_TASK(cmd)->t_transport_active=0 so that transport_generic_handle_data
+ * can be called from HW target mode interrupt code. This is safe
+ * to be called with transport_off=1 before the CMD_TFO(cmd)->write_pending
+ * because the se_cmd->se_lun pointer is not being cleared.
+ */
+ transport_cmd_check_stop(cmd, 1, 0);
+
+ /*
* Call the fabric write_pending function here to let the
* frontend know that WRITE buffers are ready.
*/
ret = CMD_TFO(cmd)->write_pending(cmd);
- if (ret < 0) {
- transport_cmd_check_stop(cmd, 1, 0);
+ if (ret < 0)
return ret;
- }
- transport_cmd_check_stop(cmd, 1, 0);
return PYX_TRANSPORT_WRITE_PENDING;
}
--
1.5.6.5
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 2/2] target: Convert se_nacl->nacl_sess_lock to use spin_lock_irq()
2010-12-13 23:58 [PATCH 0/2] target: Updates for HW target mode Nicholas A. Bellinger
2010-12-13 23:58 ` [PATCH 1/2] target: Fix tfo->write_pending() fabric callback ordering Nicholas A. Bellinger
@ 2010-12-13 23:58 ` Nicholas A. Bellinger
1 sibling, 0 replies; 3+ messages in thread
From: Nicholas A. Bellinger @ 2010-12-13 23:58 UTC (permalink / raw)
To: linux-scsi, Christoph Hellwig
Cc: Mike Christie, Hannes Reinecke, FUJITA Tomonori, James Bottomley,
Nicholas Bellinger
From: Nicholas Bellinger <nab@linux-iscsi.org>
This patch converts the usage of se_nacl->nacl_sess_lock to use
spin_[un]lock_irq in __transport_register_session() and
transport_deregister_session_configfs(), along with the iSCSI specific
fabric_lib TransportID handlers in target_core_fabric_lib.c
This patch also changes PRI logic in core_scsi3_pri_read_full_status() to
increment pr_reg->pr_res_holders and drop pr_tmpl->registration_lock while
calling TPG_TFO(se_tpg)->tpg_get_pr_transport_id*() for the iSCSI TransportID
case that needs to obtain se_nacl->nacl_sess_lock.
This has been done to allow transport_deregister_session_configfs() to be called
from interrupt context for HW target mode.
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
(cherry picked from commit cc8a8c3cb55293822871ce40c2cec73163206203)
---
drivers/target/target_core_fabric_lib.c | 8 ++++----
drivers/target/target_core_pr.c | 11 +++++++++++
drivers/target/target_core_transport.c | 8 ++++----
3 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/drivers/target/target_core_fabric_lib.c b/drivers/target/target_core_fabric_lib.c
index f4b34d3..3e6986d 100644
--- a/drivers/target/target_core_fabric_lib.c
+++ b/drivers/target/target_core_fabric_lib.c
@@ -229,7 +229,7 @@ u32 iscsi_get_pr_transport_id(
u32 off = 4, padding = 0;
u16 len = 0;
- spin_lock(&se_nacl->nacl_sess_lock);
+ spin_lock_irq(&se_nacl->nacl_sess_lock);
/*
* Set PROTOCOL IDENTIFIER to 5h for iSCSI
*/
@@ -293,7 +293,7 @@ u32 iscsi_get_pr_transport_id(
buf[off+len] = '\0'; off++;
len += 7;
}
- spin_unlock(&se_nacl->nacl_sess_lock);
+ spin_unlock_irq(&se_nacl->nacl_sess_lock);
/*
* The ADDITIONAL LENGTH field specifies the number of bytes that follow
* in the TransportID. The additional length shall be at least 20 and
@@ -323,7 +323,7 @@ u32 iscsi_get_pr_transport_id_len(
{
u32 len = 0, padding = 0;
- spin_lock(&se_nacl->nacl_sess_lock);
+ spin_lock_irq(&se_nacl->nacl_sess_lock);
len = strlen(se_nacl->initiatorname);
/*
* Add extra byte for NULL terminator
@@ -342,7 +342,7 @@ u32 iscsi_get_pr_transport_id_len(
*format_code = 1;
} else
*format_code = 0;
- spin_unlock(&se_nacl->nacl_sess_lock);
+ spin_unlock_irq(&se_nacl->nacl_sess_lock);
/*
* The ADDITIONAL LENGTH field specifies the number of bytes that follow
* in the TransportID. The additional length shall be at least 20 and
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 5d6c545..6b275bb 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -4042,6 +4042,10 @@ static int core_scsi3_pri_read_full_status(struct se_cmd *cmd)
se_nacl = pr_reg->pr_reg_nacl;
se_tpg = pr_reg->pr_reg_nacl->se_tpg;
add_desc_len = 0;
+
+ atomic_inc(&pr_reg->pr_res_holders);
+ smp_mb__after_atomic_inc();
+ spin_unlock(&pr_tmpl->registration_lock);
/*
* Determine expected length of $FABRIC_MOD specific
* TransportID full status descriptor..
@@ -4052,6 +4056,9 @@ static int core_scsi3_pri_read_full_status(struct se_cmd *cmd)
if ((exp_desc_len + add_len) > cmd->data_length) {
printk(KERN_WARNING "SPC-3 PRIN READ_FULL_STATUS ran"
" out of buffer: %d\n", cmd->data_length);
+ spin_lock(&pr_tmpl->registration_lock);
+ atomic_dec(&pr_reg->pr_res_holders);
+ smp_mb__after_atomic_dec();
break;
}
/*
@@ -4110,6 +4117,10 @@ static int core_scsi3_pri_read_full_status(struct se_cmd *cmd)
*/
desc_len = TPG_TFO(se_tpg)->tpg_get_pr_transport_id(se_tpg,
se_nacl, pr_reg, &format_code, &buf[off+4]);
+
+ spin_lock(&pr_tmpl->registration_lock);
+ atomic_dec(&pr_reg->pr_res_holders);
+ smp_mb__after_atomic_dec();
/*
* Set the ADDITIONAL DESCRIPTOR LENGTH
*/
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 019ccbc..dbc2800 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -474,7 +474,7 @@ void __transport_register_session(
&buf[0], PR_REG_ISID_LEN);
se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
}
- spin_lock_bh(&se_nacl->nacl_sess_lock);
+ spin_lock_irq(&se_nacl->nacl_sess_lock);
/*
* The se_nacl->nacl_sess pointer will be set to the
* last active I_T Nexus for each struct se_node_acl.
@@ -483,7 +483,7 @@ void __transport_register_session(
list_add_tail(&se_sess->sess_acl_list,
&se_nacl->acl_sess_list);
- spin_unlock_bh(&se_nacl->nacl_sess_lock);
+ spin_unlock_irq(&se_nacl->nacl_sess_lock);
}
list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
@@ -513,7 +513,7 @@ void transport_deregister_session_configfs(struct se_session *se_sess)
*/
se_nacl = se_sess->se_node_acl;
if ((se_nacl)) {
- spin_lock_bh(&se_nacl->nacl_sess_lock);
+ spin_lock_irq(&se_nacl->nacl_sess_lock);
list_del(&se_sess->sess_acl_list);
/*
* If the session list is empty, then clear the pointer.
@@ -527,7 +527,7 @@ void transport_deregister_session_configfs(struct se_session *se_sess)
se_nacl->acl_sess_list.prev,
struct se_session, sess_acl_list);
}
- spin_unlock_bh(&se_nacl->nacl_sess_lock);
+ spin_unlock_irq(&se_nacl->nacl_sess_lock);
}
}
EXPORT_SYMBOL(transport_deregister_session_configfs);
--
1.5.6.5
^ permalink raw reply related [flat|nested] 3+ messages in thread