From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
(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
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