scsi/lun: simplify task submission path

Removed task `pending` queue. All tasks were
temporarily put in this queue just to be moved
out of it yet within the same reactor cycle.

Change-Id: I32d402f7abd3cfa21c263f41149425abdc71992f
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/393911
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

lib/scsi/dev.c

@@ -203,10 +203,7 @@ spdk_scsi_dev_queue_task(struct spdk_scsi_dev *dev,
 {
 	assert(task != NULL);
 
-	if (spdk_scsi_lun_append_task(task->lun, task) == 0) {
+	spdk_scsi_lun_execute_task(task->lun, task);
-		/* ready to execute, disk is valid for LUN access */
-		spdk_scsi_lun_execute_tasks(task->lun);
-	}
 }
 
 static struct spdk_scsi_port *

lib/scsi/lun.c

@@ -49,46 +49,18 @@ spdk_scsi_lun_complete_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *ta
 	task->cpl_fn(task);
 }
 
-static int
-spdk_scsi_lun_clear_all(struct spdk_scsi_lun *lun)
-{
-	struct spdk_scsi_task *task, *task_tmp;
-	int rc = 0;
-
-	/*
-	 * This function is called from one location, after the backend LUN
-	 * device was reset. If there are active tasks in the backend, it
-	 * means that LUN reset fails, and we return and set failure status
-	 * to LUN reset task. If LUN reset succeeds, we need to abort any
-	 * pending tasks..
-	 *
-	 * ( 'tasks' = active, and 'pending' = newest)
-	 */
-
-	if (!TAILQ_EMPTY(&lun->tasks)) {
-		SPDK_ERRLOG("lun->tasks should be empty after reset\n");
-		rc = -1;
-	}
-
-	TAILQ_FOREACH_SAFE(task, &lun->pending_tasks, scsi_link, task_tmp) {
-		TAILQ_REMOVE(&lun->pending_tasks, task, scsi_link);
-		spdk_scsi_task_set_status(task, SPDK_SCSI_STATUS_CHECK_CONDITION,
-					  SPDK_SCSI_SENSE_ABORTED_COMMAND,
-					  SPDK_SCSI_ASC_NO_ADDITIONAL_SENSE,
-					  SPDK_SCSI_ASCQ_CAUSE_NOT_REPORTABLE);
-		spdk_trace_record(TRACE_SCSI_TASK_DONE, lun->dev->id, 0, (uintptr_t)task, 0);
-		task->cpl_fn(task);
-	}
-
-	return rc;
-}
-
 void
 spdk_scsi_lun_complete_mgmt_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
 {
 	if (task->function == SPDK_SCSI_TASK_FUNC_LUN_RESET &&
 	    task->status == SPDK_SCSI_STATUS_GOOD) {
-		if (spdk_scsi_lun_clear_all(task->lun)) {
+		/*
+		 * The backend LUN device was just reset. If there are active tasks
+		 * in the backend, it means that LUN reset fails, and we set failure
+		 * status to LUN reset task.
+		 */
+		if (spdk_scsi_lun_has_pending_tasks(lun)) {
+			SPDK_ERRLOG("lun->tasks should be empty after reset\n");
 			task->response = SPDK_SCSI_TASK_MGMT_RESP_TARGET_FAILURE;
 		}
 	}
@@ -178,23 +150,13 @@ spdk_scsi_task_process_null_lun(struct spdk_scsi_task *task)
 	}
 }
 
-int
-spdk_scsi_lun_append_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
-{
-	TAILQ_INSERT_TAIL(&lun->pending_tasks, task, scsi_link);
-	return 0;
-}
-
 void
-spdk_scsi_lun_execute_tasks(struct spdk_scsi_lun *lun)
+spdk_scsi_lun_execute_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
 {
-	struct spdk_scsi_task *task, *task_tmp;
 	int rc;
 
-	TAILQ_FOREACH_SAFE(task, &lun->pending_tasks, scsi_link, task_tmp) {
 	task->status = SPDK_SCSI_STATUS_GOOD;
 	spdk_trace_record(TRACE_SCSI_TASK_START, lun->dev->id, task->length, (uintptr_t)task, 0);
-		TAILQ_REMOVE(&lun->pending_tasks, task, scsi_link);
 	TAILQ_INSERT_TAIL(&lun->tasks, task, scsi_link);
 	if (!lun->removed) {
 		rc = spdk_bdev_scsi_execute(task);
@@ -218,7 +180,6 @@ spdk_scsi_lun_execute_tasks(struct spdk_scsi_lun *lun)
 		abort();
 	}
 }
-}
 
 static void
 spdk_scsi_lun_hotplug(void *arg)
@@ -299,7 +260,6 @@ spdk_scsi_lun_construct(const char *name, struct spdk_bdev *bdev,
 	}
 
 	TAILQ_INIT(&lun->tasks);
-	TAILQ_INIT(&lun->pending_tasks);
 
 	lun->bdev = bdev;
 	lun->io_channel = NULL;
@@ -393,5 +353,5 @@ spdk_scsi_lun_get_dev(const struct spdk_scsi_lun *lun)
 bool
 spdk_scsi_lun_has_pending_tasks(const struct spdk_scsi_lun *lun)
 {
-	return !TAILQ_EMPTY(&lun->pending_tasks) || !TAILQ_EMPTY(&lun->tasks);
+	return !TAILQ_EMPTY(&lun->tasks);
 }

lib/scsi/scsi_internal.h

@@ -110,8 +110,7 @@ struct spdk_scsi_lun {
 	/** Argument for hotremove_cb */
 	void *hotremove_ctx;
 
-	TAILQ_HEAD(tasks, spdk_scsi_task) tasks;			/* submitted tasks */
+	TAILQ_HEAD(tasks, spdk_scsi_task) tasks;			/* pending tasks */
-	TAILQ_HEAD(pending_tasks, spdk_scsi_task) pending_tasks;	/* pending tasks */
 };
 
 struct spdk_lun_db_entry {
@@ -131,8 +130,7 @@ _spdk_scsi_lun *spdk_scsi_lun_construct(const char *name, struct spdk_bdev *bdev
 					void *hotremove_ctx);
 int spdk_scsi_lun_destruct(struct spdk_scsi_lun *lun);
 
-int spdk_scsi_lun_append_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task);
+void spdk_scsi_lun_execute_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task);
-void spdk_scsi_lun_execute_tasks(struct spdk_scsi_lun *lun);
 int spdk_scsi_lun_task_mgmt_execute(struct spdk_scsi_task *task, enum spdk_scsi_task_func func);
 void spdk_scsi_lun_complete_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task);
 void spdk_scsi_lun_complete_mgmt_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task);

test/unit/lib/scsi/dev.c/dev_ut.c

@@ -157,14 +157,8 @@ spdk_scsi_lun_task_mgmt_execute(struct spdk_scsi_task *task, enum spdk_scsi_task
 	return 0;
 }
 
-int
-spdk_scsi_lun_append_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
-{
-	return 0;
-}
-
 void
-spdk_scsi_lun_execute_tasks(struct spdk_scsi_lun *lun)
+spdk_scsi_lun_execute_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *task)
 {
 }
 

test/unit/lib/scsi/lun.c/lun_ut.c

@@ -209,10 +209,6 @@ lun_construct(void)
 	lun = spdk_scsi_lun_construct("lun0", &bdev, NULL, NULL);
 
 	SPDK_CU_ASSERT_FATAL(lun != NULL);
-	if (lun != NULL) {
-		SPDK_CU_ASSERT_FATAL(TAILQ_EMPTY(&lun->pending_tasks));
-	}
-
 	return lun;
 }
 
@@ -275,12 +271,7 @@ lun_task_mgmt_execute_abort_task_not_supported(void)
 	task.lun = lun;
 	task.cdb = cdb;
 
-	spdk_scsi_lun_append_task(lun, &task);
+	spdk_scsi_lun_execute_task(lun, &task);
-
-	/* task should now be on the pending_task list */
-	CU_ASSERT(!TAILQ_EMPTY(&lun->pending_tasks));
-
-	spdk_scsi_lun_execute_tasks(lun);
 
 	/* task should now be on the tasks list */
 	CU_ASSERT(!TAILQ_EMPTY(&lun->tasks));
@@ -341,12 +332,7 @@ lun_task_mgmt_execute_abort_task_all_not_supported(void)
 	task.lun = lun;
 	task.cdb = cdb;
 
-	spdk_scsi_lun_append_task(lun, &task);
+	spdk_scsi_lun_execute_task(lun, &task);
-
-	/* task should now be on the pending_task list */
-	CU_ASSERT(!TAILQ_EMPTY(&lun->pending_tasks));
-
-	spdk_scsi_lun_execute_tasks(lun);
 
 	/* task should now be on the tasks list */
 	CU_ASSERT(!TAILQ_EMPTY(&lun->tasks));
@@ -515,17 +501,12 @@ lun_execute_scsi_task_pending(void)
 	g_lun_execute_fail = false;
 	g_lun_execute_status = SPDK_SCSI_TASK_PENDING;
 
-	spdk_scsi_lun_append_task(lun, &task);
+	/* the tasks list should still be empty since it has not been
-
-	/* task should now be on the pending_task list */
-	CU_ASSERT(!TAILQ_EMPTY(&lun->pending_tasks));
-
-	/* but the tasks list should still be empty since it has not been
 	   executed yet
 	 */
 	CU_ASSERT(TAILQ_EMPTY(&lun->tasks));
 
-	spdk_scsi_lun_execute_tasks(lun);
+	spdk_scsi_lun_execute_task(lun, &task);
 
 	/* Assert the task has been successfully added to the tasks queue */
 	CU_ASSERT(!TAILQ_EMPTY(&lun->tasks));
@@ -553,17 +534,12 @@ lun_execute_scsi_task_complete(void)
 	g_lun_execute_fail = false;
 	g_lun_execute_status = SPDK_SCSI_TASK_COMPLETE;
 
-	spdk_scsi_lun_append_task(lun, &task);
+	/* the tasks list should still be empty since it has not been
-
-	/* task should now be on the pending_task list */
-	CU_ASSERT(!TAILQ_EMPTY(&lun->pending_tasks));
-
-	/* but the tasks list should still be empty since it has not been
 	   executed yet
 	 */
 	CU_ASSERT(TAILQ_EMPTY(&lun->tasks));
 
-	spdk_scsi_lun_execute_tasks(lun);
+	spdk_scsi_lun_execute_task(lun, &task);
 
 	/* Assert the task has not been added to the tasks queue */
 	CU_ASSERT(TAILQ_EMPTY(&lun->tasks));