Merge tag 'isci-for-3.5' into misc

isci update for 3.5

1/ Rework remote-node-context (RNC) handling for proper management of
   the silicon state machine in error handling and hot-plug conditions.
   Further details below, suffice to say if the RNC is mismanaged the
   silicon state machines may lock up.

2/ Refactor the initialization code to be reused for suspend/resume support

3/ Miscellaneous bug fixes to address discovery issues and hardware
   compatibility.

RNC rework details from Jeff Skirvin:

In the controller, devices as they appear on a SAS domain (or
direct-attached SATA devices) are represented by memory structures known
as "Remote Node Contexts" (RNCs).  These structures are transferred from
main memory to the controller using a set of register commands; these
commands include setting up the context ("posting"), removing the
context ("invalidating"), and commands to control the scheduling of
commands and connections to that remote device ("suspensions" and
"resumptions").  There is a similar path to control RNC scheduling from
the protocol engine, which interprets the results of command and data
transmission and reception.

In general, the controller chooses among non-suspended RNCs to find one
that has work requiring scheduling the transmission of command and data
frames to a target.  Likewise, when a target tries to return data back
to the initiator, the state of the RNC is used by the controller to
determine how to treat the incoming request. As an example, if the RNC
is in the state "TX/RX Suspended", incoming SSP connection requests from
the target will be rejected by the controller hardware.  When an RNC is
"TX Suspended", it will not be selected by the controller hardware to
start outgoing command or data operations (with certain priority-based
exceptions).

As mentioned above, there are two sources for management of the RNC
states: commands from driver software, and the result of transmission
and reception conditions of commands and data signaled by the controller
hardware.  As an example of the latter, if an outgoing SSP command ends
with a OPEN_REJECT(BAD_DESTINATION) status, the RNC state will
transition to the "TX Suspended" state, and this is signaled by the
controller hardware in the status to the completion of the pending
command as well as signaled in a controller hardware event.  Examples of
the former are included in the patch changelogs.

Driver software is required to suspend the RNC in a "TX/RX Suspended"
condition before any outstanding commands can be terminated.  Failure to
guarantee this can lead to a complete hardware hang condition.  Earlier
versions of the driver software did not guarantee that an RNC was
correctly managed before I/O termination, and so operated in an unsafe
way.

Further, the driver performed unnecessary contortions to preserve the
remote device command state and so was more complicated than it needed
to be.  A simplifying driver assumption is that once an I/O has entered
the error handler path without having completed in the target, the
requirement on the driver is that all use of the sas_task must end.
Beyond that, recovery of operation is dependent on libsas and other
components to reset, rediscover and reconfigure the device before normal
operation can restart.  In the driver, this simplifying assumption meant
that the RNC management could be reduced to entry into the suspended
state, terminating the targeted I/O request, and resuming the RNC as
needed for device-specific management such as an SSP Abort Task or LUN
Reset Management request.

1 files changed, 1 insertions, 131 deletions

diff --git a/drivers/scsi/isci/task.h b/drivers/scsi/isci/task.h
index 7b6d0e32fd9b..9c06cbad1d26 100644
--- a/drivers/scsi/isci/task.h
+++ b/drivers/scsi/isci/task.h
@@ -63,19 +63,6 @@
 struct isci_request;
 
 /**
- * enum isci_tmf_cb_state - This enum defines the possible states in which the
- *    TMF callback function is invoked during the TMF execution process.
- *
- *
- */
-enum isci_tmf_cb_state {
-
-	isci_tmf_init_state = 0,
-	isci_tmf_started,
-	isci_tmf_timed_out
-};
-
-/**
  * enum isci_tmf_function_codes - This enum defines the possible preparations
  *    of task management requests.
  *
@@ -87,6 +74,7 @@ enum isci_tmf_function_codes {
 	isci_tmf_ssp_task_abort = TMF_ABORT_TASK,
 	isci_tmf_ssp_lun_reset  = TMF_LU_RESET,
 };
+
 /**
  * struct isci_tmf - This class represents the task management object which
  *    acts as an interface to libsas for processing task management requests
@@ -106,15 +94,6 @@ struct isci_tmf {
 	u16 io_tag;
 	enum isci_tmf_function_codes tmf_code;
 	int status;
-
-	/* The optional callback function allows the user process to
-	 * track the TMF transmit / timeout conditions.
-	 */
-	void (*cb_state_func)(
-		enum isci_tmf_cb_state,
-		struct isci_tmf *, void *);
-	void *cb_data;
-
 };
 
 static inline void isci_print_tmf(struct isci_host *ihost, struct isci_tmf *tmf)
@@ -208,113 +187,4 @@ int isci_queuecommand(
 	struct scsi_cmnd *scsi_cmd,
 	void (*donefunc)(struct scsi_cmnd *));
 
-/**
- * enum isci_completion_selection - This enum defines the possible actions to
- *    take with respect to a given request's notification back to libsas.
- *
- *
- */
-enum isci_completion_selection {
-
-	isci_perform_normal_io_completion,      /* Normal notify (task_done) */
-	isci_perform_aborted_io_completion,     /* No notification.   */
-	isci_perform_error_io_completion        /* Use sas_task_abort */
-};
-
-/**
- * isci_task_set_completion_status() - This function sets the completion status
- *    for the request.
- * @task: This parameter is the completed request.
- * @response: This parameter is the response code for the completed task.
- * @status: This parameter is the status code for the completed task.
- *
-* @return The new notification mode for the request.
-*/
-static inline enum isci_completion_selection
-isci_task_set_completion_status(
-	struct sas_task *task,
-	enum service_response response,
-	enum exec_status status,
-	enum isci_completion_selection task_notification_selection)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&task->task_state_lock, flags);
-
-	/* If a device reset is being indicated, make sure the I/O
-	* is in the error path.
-	*/
-	if (task->task_state_flags & SAS_TASK_NEED_DEV_RESET) {
-		/* Fail the I/O to make sure it goes into the error path. */
-		response = SAS_TASK_UNDELIVERED;
-		status = SAM_STAT_TASK_ABORTED;
-
-		task_notification_selection = isci_perform_error_io_completion;
-	}
-	task->task_status.resp = response;
-	task->task_status.stat = status;
-
-	switch (task->task_proto) {
-
-	case SAS_PROTOCOL_SATA:
-	case SAS_PROTOCOL_STP:
-	case SAS_PROTOCOL_SATA | SAS_PROTOCOL_STP:
-
-		if (task_notification_selection
-		    == isci_perform_error_io_completion) {
-			/* SATA/STP I/O has it's own means of scheduling device
-			* error handling on the normal path.
-			*/
-			task_notification_selection
-				= isci_perform_normal_io_completion;
-		}
-		break;
-	default:
-		break;
-	}
-
-	switch (task_notification_selection) {
-
-	case isci_perform_error_io_completion:
-
-		if (task->task_proto == SAS_PROTOCOL_SMP) {
-			/* There is no error escalation in the SMP case.
-			 * Convert to a normal completion to avoid the
-			 * timeout in the discovery path and to let the
-			 * next action take place quickly.
-			 */
-			task_notification_selection
-				= isci_perform_normal_io_completion;
-
-			/* Fall through to the normal case... */
-		} else {
-			/* Use sas_task_abort */
-			/* Leave SAS_TASK_STATE_DONE clear
-			 * Leave SAS_TASK_AT_INITIATOR set.
-			 */
-			break;
-		}
-
-	case isci_perform_aborted_io_completion:
-		/* This path can occur with task-managed requests as well as
-		 * requests terminated because of LUN or device resets.
-		 */
-		/* Fall through to the normal case... */
-	case isci_perform_normal_io_completion:
-		/* Normal notification (task_done) */
-		task->task_state_flags |= SAS_TASK_STATE_DONE;
-		task->task_state_flags &= ~(SAS_TASK_AT_INITIATOR |
-					    SAS_TASK_STATE_PENDING);
-		break;
-	default:
-		WARN_ONCE(1, "unknown task_notification_selection: %d\n",
-			 task_notification_selection);
-		break;
-	}
-
-	spin_unlock_irqrestore(&task->task_state_lock, flags);
-
-	return task_notification_selection;
-
-}
 #endif /* !defined(_SCI_TASK_H_) */