isci: Qualify when the host lock is managed for STP/SATA callbacks.

In the case of internal discovery related STP/SATA I/O started
through sas_execute_task the host lock is not taken by libsas before
calling lldd_execute_task, so the lock should not be managed before
calling back to libsas through task->task_done or sas_task_abort.
Signed-off-by: NJeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/scsi/isci/request.c

@@ -53,7 +53,6 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <scsi/sas_ata.h>
 #include "isci.h"
 #include "scic_remote_device.h"
 #include "scic_io_request.h"
@@ -452,22 +451,11 @@ int isci_request_execute(
 			task->task_state_flags |= SAS_TASK_NEED_DEV_RESET;
 			spin_unlock_irqrestore(&task->task_state_lock, flags);
 
-			/* Cause this task to be scheduled in the SCSI error handler
-			* thread.
+			/* Cause this task to be scheduled in the SCSI error
+			* handler thread.
 			*/
-			if (dev_is_sata(task->dev)) {
-				/* Since we are still in the submit path, and since
-				* libsas takes the host lock on behalf of SATA
-				* devices before I/O starts, we need to unlock
-				* before we can put the task in the error path.
-				*/
-				raw_local_irq_save(flags);
-				spin_unlock(isci_host->shost->host_lock);
-				sas_task_abort(task);
-				spin_lock(isci_host->shost->host_lock);
-				raw_local_irq_restore(flags);
-			} else
-				sas_task_abort(task);
+			isci_execpath_callback(isci_host, task,
+					       sas_task_abort);
 
 			/* Change the status, since we are holding
 			* the I/O until it is managed by the SCSI

drivers/scsi/isci/sata.c

@@ -299,7 +299,6 @@ int isci_task_send_lu_reset_sata(
 {
 	struct isci_tmf tmf;
 	int ret = TMF_RESP_FUNC_FAILED;
-	unsigned long flags;
 
 	/* Send the soft reset to the target */
 	#define ISCI_SRST_TIMEOUT_MS 25000 /* 25 second timeout. */

drivers/scsi/isci/task.c

@@ -55,7 +55,6 @@
 
 #include <linux/completion.h>
 #include <linux/irqflags.h>
-#include <scsi/sas_ata.h>
 #include "scic_task_request.h"
 #include "scic_remote_device.h"
 #include "scic_io_request.h"
@@ -93,26 +92,13 @@ static void isci_task_refuse(struct isci_host *ihost, struct sas_task *task,
 		case isci_perform_normal_io_completion:
 			/* Normal notification (task_done) */
 			dev_dbg(&ihost->pdev->dev,
-				"%s: Normal - task = %p, response=%d, status=%d\n",
+				"%s: Normal - task = %p, response=%d, "
+				"status=%d\n",
 				__func__, task, response, status);
 
 			task->lldd_task = NULL;
-			if (dev_is_sata(task->dev)) {
-				/* Since we are still in the submit path, and since
-				* libsas takes the host lock on behalf of SATA
-				* devices before I/O starts, we need to unlock
-				* before we can call back and report the I/O
-				* submission error.
-				*/
-				unsigned long flags;
 
-				raw_local_irq_save(flags);
-				spin_unlock(ihost->shost->host_lock);
-				task->task_done(task);
-				spin_lock(ihost->shost->host_lock);
-				raw_local_irq_restore(flags);
-			} else
-				task->task_done(task);
+			isci_execpath_callback(ihost, task, task->task_done);
 			break;
 
 		case isci_perform_aborted_io_completion:
@@ -120,16 +106,19 @@ static void isci_task_refuse(struct isci_host *ihost, struct sas_task *task,
 			* abort path.
 			*/
 			dev_warn(&ihost->pdev->dev,
-				 "%s: Aborted - task = %p, response=%d, status=%d\n",
+				 "%s: Aborted - task = %p, response=%d, "
+				"status=%d\n",
 				 __func__, task, response, status);
 			break;
 
 		case isci_perform_error_io_completion:
 			/* Use sas_task_abort */
 			dev_warn(&ihost->pdev->dev,
-				 "%s: Error - task = %p, response=%d, status=%d\n",
+				 "%s: Error - task = %p, response=%d, "
+				"status=%d\n",
 				 __func__, task, response, status);
-			sas_task_abort(task);
+
+			isci_execpath_callback(ihost, task, sas_task_abort);
 			break;
 
 		default:

drivers/scsi/isci/task.h

@@ -56,6 +56,8 @@
 #if !defined(_ISCI_TASK_H_)
 #define _ISCI_TASK_H_
 
+#include <scsi/sas_ata.h>
+
 struct isci_request;
 struct isci_host;
 
@@ -332,5 +334,40 @@ isci_task_set_completion_status(
 	return task_notification_selection;
 
 }
+/**
+* isci_execpath_callback() - This function is called from the task
+* execute path when the task needs to callback libsas about the submit-time
+* task failure.  The callback occurs either through the task's done function
+* or through sas_task_abort.  In the case of regular non-discovery SATA/STP I/O
+* requests, libsas takes the host lock before calling execute task.  Therefore
+* in this situation the host lock must be managed before calling the func.
+*
+* @ihost: This parameter is the controller to which the I/O request was sent.
+* @task: This parameter is the I/O request.
+* @func: This parameter is the function to call in the correct context.
+* @status: This parameter is the status code for the completed task.
+*
+*/
+static inline void isci_execpath_callback(
+	struct isci_host *ihost,
+	struct sas_task  *task,
+	void (*func)(struct sas_task *))
+{
+	unsigned long flags;
+
+	if (dev_is_sata(task->dev) && task->uldd_task) {
+		/* Since we are still in the submit path, and since
+		* libsas takes the host lock on behalf of SATA
+		* devices before I/O starts (in the non-discovery case),
+		* we need to unlock before we can call the callback function.
+		*/
+		raw_local_irq_save(flags);
+		spin_unlock(ihost->shost->host_lock);
+		func(task);
+		spin_lock(ihost->shost->host_lock);
+		raw_local_irq_restore(flags);
+	} else
+		func(task);
+}
 
 #endif /* !defined(_SCI_TASK_H_) */