isci: merge ssp task management substates into primary state machine

Remove usage of the request substate machine for ssp task management
requests identified by:
	ireq->ttype == tmf_task && dev->dev_type == SAS_END_DEV;

The only routine that checks the base 'started' state is
scic_sds_io_request_tc_completion which calls the substate machine
handler if we are not in the 'started' state or we are 'started' and no
substate machine is defined.  This routine requires no conversion
because we have transitioned out of 'started' and the substate routine
will be called naturally as a result.

There are also no side effects of this conversion on exiting the
'started', state because it only stops the substate machine, which is no
longer relevant for this transaction type.

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 164 insertions, 21 deletions

diff --git a/drivers/scsi/isci/request.c b/drivers/scsi/isci/request.c
index 48e2dac7252..5f516811055 100644
--- a/drivers/scsi/isci/request.c
+++ b/drivers/scsi/isci/request.c
@@ -656,7 +656,7 @@ enum sci_status scic_sds_io_request_frame_handler(
  * @sci_req: This parameter specifies the request object for which to copy
  *    the response data.
  */
-void scic_sds_io_request_copy_response(struct scic_sds_request *sci_req)
+static void scic_sds_io_request_copy_response(struct scic_sds_request *sci_req)
 {
 	void *resp_buf;
 	u32 len;
@@ -978,7 +978,6 @@ scic_sds_io_request_tc_completion(struct scic_sds_request *request, u32 completi
 		sci_base_state_machine_get_state(&request->state_machine));
 
 	return SCI_FAILURE_INVALID_STATE;
-
 }
 
 /*
@@ -1151,9 +1150,119 @@ static enum sci_status scic_sds_request_aborting_state_frame_handler(
 	return SCI_SUCCESS;
 }
 
+/**
+ * This method processes the completions transport layer (TL) status to
+ *    determine if the RAW task management frame was sent successfully. If the
+ *    raw frame was sent successfully, then the state for the task request
+ *    transitions to waiting for a response frame.
+ * @sci_req: This parameter specifies the request for which the TC
+ *    completion was received.
+ * @completion_code: This parameter indicates the completion status information
+ *    for the TC.
+ *
+ * Indicate if the tc completion handler was successful. SCI_SUCCESS currently
+ * this method always returns success.
+ */
+static enum sci_status scic_sds_ssp_task_request_await_tc_completion_tc_completion_handler(
+	struct scic_sds_request *sci_req,
+	u32 completion_code)
+{
+	switch (SCU_GET_COMPLETION_TL_STATUS(completion_code)) {
+	case SCU_MAKE_COMPLETION_STATUS(SCU_TASK_DONE_GOOD):
+		scic_sds_request_set_status(sci_req, SCU_TASK_DONE_GOOD,
+					    SCI_SUCCESS);
+
+		sci_base_state_machine_change_state(&sci_req->state_machine,
+			SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_RESPONSE);
+		break;
+
+	case SCU_MAKE_COMPLETION_STATUS(SCU_TASK_DONE_ACK_NAK_TO):
+		/*
+		 * Currently, the decision is to simply allow the task request to
+		 * timeout if the task IU wasn't received successfully.
+		 * There is a potential for receiving multiple task responses if we
+		 * decide to send the task IU again. */
+		dev_warn(scic_to_dev(sci_req->owning_controller),
+			 "%s: TaskRequest:0x%p CompletionCode:%x - "
+			 "ACK/NAK timeout\n",
+			 __func__,
+			 sci_req,
+			 completion_code);
+
+		sci_base_state_machine_change_state(&sci_req->state_machine,
+			SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_RESPONSE);
+		break;
+
+	default:
+		/*
+		 * All other completion status cause the IO to be complete.  If a NAK
+		 * was received, then it is up to the user to retry the request. */
+		scic_sds_request_set_status(
+			sci_req,
+			SCU_NORMALIZE_COMPLETION_STATUS(completion_code),
+			SCI_FAILURE_CONTROLLER_SPECIFIC_IO_ERR
+			);
+
+		sci_base_state_machine_change_state(&sci_req->state_machine,
+			SCI_BASE_REQUEST_STATE_COMPLETED);
+		break;
+	}
+
+	return SCI_SUCCESS;
+}
+
+/**
+ * This method is responsible for processing a terminate/abort request for this
+ *    TC while the request is waiting for the task management response
+ *    unsolicited frame.
+ * @sci_req: This parameter specifies the request for which the
+ *    termination was requested.
+ *
+ * This method returns an indication as to whether the abort request was
+ * successfully handled. need to update to ensure the received UF doesn't cause
+ * damage to subsequent requests (i.e. put the extended tag in a holding
+ * pattern for this particular device).
+ */
+static enum sci_status scic_sds_ssp_task_request_await_tc_response_abort_handler(
+	struct scic_sds_request *request)
+{
+	sci_base_state_machine_change_state(&request->state_machine,
+			SCI_BASE_REQUEST_STATE_ABORTING);
+	sci_base_state_machine_change_state(&request->state_machine,
+			SCI_BASE_REQUEST_STATE_COMPLETED);
+	return SCI_SUCCESS;
+}
+
+/**
+ * This method processes an unsolicited frame while the task mgmt request is
+ *    waiting for a response frame.  It will copy the response data, release
+ *    the unsolicited frame, and transition the request to the
+ *    SCI_BASE_REQUEST_STATE_COMPLETED state.
+ * @sci_req: This parameter specifies the request for which the
+ *    unsolicited frame was received.
+ * @frame_index: This parameter indicates the unsolicited frame index that
+ *    should contain the response.
+ *
+ * This method returns an indication of whether the TC response frame was
+ * handled successfully or not. SCI_SUCCESS Currently this value is always
+ * returned and indicates successful processing of the TC response. Should
+ * probably update to check frame type and make sure it is a response frame.
+ */
+static enum sci_status scic_sds_ssp_task_request_await_tc_response_frame_handler(
+	struct scic_sds_request *request,
+	u32 frame_index)
+{
+	scic_sds_io_request_copy_response(request);
+
+	sci_base_state_machine_change_state(&request->state_machine,
+		SCI_BASE_REQUEST_STATE_COMPLETED);
+	scic_sds_controller_release_frame(request->owning_controller,
+			frame_index);
+	return SCI_SUCCESS;
+}
+
 static const struct scic_sds_io_request_state_handler scic_sds_request_state_handler_table[] = {
-	[SCI_BASE_REQUEST_STATE_INITIAL] = {
-	},
+	[SCI_BASE_REQUEST_STATE_INITIAL] = { },
 	[SCI_BASE_REQUEST_STATE_CONSTRUCTED] = {
 		.start_handler		= scic_sds_request_constructed_state_start_handler,
 		.abort_handler		= scic_sds_request_constructed_state_abort_handler,
@@ -1163,6 +1272,14 @@ static const struct scic_sds_io_request_state_handler scic_sds_request_state_han
 		.tc_completion_handler	= scic_sds_request_started_state_tc_completion_handler,
 		.frame_handler		= scic_sds_request_started_state_frame_handler,
 	},
+	[SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_COMPLETION] = {
+		.abort_handler		= scic_sds_request_started_state_abort_handler,
+		.tc_completion_handler	= scic_sds_ssp_task_request_await_tc_completion_tc_completion_handler,
+	},
+	[SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_RESPONSE] = {
+		.abort_handler		= scic_sds_ssp_task_request_await_tc_response_abort_handler,
+		.frame_handler		= scic_sds_ssp_task_request_await_tc_response_frame_handler,
+	},
 	[SCI_BASE_REQUEST_STATE_COMPLETED] = {
 		.complete_handler	= scic_sds_request_completed_state_complete_handler,
 	},
@@ -1171,8 +1288,7 @@ static const struct scic_sds_io_request_state_handler scic_sds_request_state_han
 		.tc_completion_handler	= scic_sds_request_aborting_state_tc_completion_handler,
 		.frame_handler		= scic_sds_request_aborting_state_frame_handler,
 	},
-	[SCI_BASE_REQUEST_STATE_FINAL] = {
-	},
+	[SCI_BASE_REQUEST_STATE_FINAL] = { },
 };
 
 
@@ -1919,6 +2035,9 @@ static void scic_sds_request_constructed_state_enter(void *object)
 static void scic_sds_request_started_state_enter(void *object)
 {
 	struct scic_sds_request *sci_req = object;
+	struct sci_base_state_machine *sm = &sci_req->state_machine;
+	struct isci_request *ireq = sci_req_to_ireq(sci_req);
+	struct domain_device *dev = sci_dev_to_domain(sci_req->target_device);
 
 	SET_STATE_HANDLER(
 		sci_req,
@@ -1926,9 +2045,13 @@ static void scic_sds_request_started_state_enter(void *object)
 		SCI_BASE_REQUEST_STATE_STARTED
 		);
 
-	/*
-	 * Most of the request state machines have a started substate machine so
-	 * start its execution on the entry to the started state. */
+	if (ireq->ttype == tmf_task && dev->dev_type == SAS_END_DEV)
+		sci_base_state_machine_change_state(sm,
+			SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_COMPLETION);
+
+	/* Most of the request state machines have a started substate machine so
+	 * start its execution on the entry to the started state.
+	 */
 	if (sci_req->has_started_substate_machine == true)
 		sci_base_state_machine_start(&sci_req->started_substate_machine);
 }
@@ -2026,6 +2149,30 @@ static void scic_sds_request_final_state_enter(void *object)
 		);
 }
 
+static void scic_sds_io_request_started_task_mgmt_await_tc_completion_substate_enter(
+	void *object)
+{
+	struct scic_sds_request *sci_req = object;
+
+	SET_STATE_HANDLER(
+		sci_req,
+		scic_sds_request_state_handler_table,
+		SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_COMPLETION
+		);
+}
+
+static void scic_sds_io_request_started_task_mgmt_await_task_response_substate_enter(
+	void *object)
+{
+	struct scic_sds_request *sci_req = object;
+
+	SET_STATE_HANDLER(
+		sci_req,
+		scic_sds_request_state_handler_table,
+		SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_RESPONSE
+		);
+}
+
 static const struct sci_base_state scic_sds_request_state_table[] = {
 	[SCI_BASE_REQUEST_STATE_INITIAL] = {
 		.enter_state = scic_sds_request_initial_state_enter,
@@ -2037,6 +2184,12 @@ static const struct sci_base_state scic_sds_request_state_table[] = {
 		.enter_state = scic_sds_request_started_state_enter,
 		.exit_state  = scic_sds_request_started_state_exit
 	},
+	[SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_COMPLETION] = {
+		.enter_state = scic_sds_io_request_started_task_mgmt_await_tc_completion_substate_enter,
+	},
+	[SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_RESPONSE] = {
+		.enter_state = scic_sds_io_request_started_task_mgmt_await_task_response_substate_enter,
+	},
 	[SCI_BASE_REQUEST_STATE_COMPLETED] = {
 		.enter_state = scic_sds_request_completed_state_enter,
 	},
@@ -2126,19 +2279,9 @@ enum sci_status scic_task_request_construct(struct scic_sds_controller *scic,
 	/* Build the common part of the request */
 	scic_sds_general_request_construct(scic, sci_dev, io_tag, sci_req);
 
-	if (dev->dev_type == SAS_END_DEV) {
+	if (dev->dev_type == SAS_END_DEV)
 		scic_sds_ssp_task_request_assign_buffers(sci_req);
-
-		sci_req->has_started_substate_machine = true;
-
-		/* Construct the started sub-state machine. */
-		sci_base_state_machine_construct(
-			&sci_req->started_substate_machine,
-			sci_req,
-			scic_sds_io_request_started_task_mgmt_substate_table,
-			SCIC_SDS_IO_REQUEST_STARTED_TASK_MGMT_SUBSTATE_AWAIT_TC_COMPLETION
-			);
-	} else if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP))
+	else if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP))
 		scic_sds_stp_request_assign_buffers(sci_req);
 	else
 		status = SCI_FAILURE_UNSUPPORTED_PROTOCOL;