runqueue: add a function that allows adding jobs to the front of the runqueue

Signed-off-by: John Crispin <blogic@openwrt.org>

runqueue.c

@@ -145,7 +145,7 @@ __runqueue_task_timeout(struct uloop_timeout *timeout)
 		runqueue_task_cancel(t, t->cancel_type);
 }
 
-void runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running)
+static void _runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running, bool first)
 {
 	struct safe_list *head;
 
@@ -166,7 +166,10 @@ void runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running
 
 	t->timeout.cb = __runqueue_task_timeout;
 	t->q = q;
-	safe_list_add(&t->list, head);
+	if (first)
+		safe_list_add_first(&t->list, head);
+	else
+		safe_list_add(&t->list, head);
 	t->cancelled = false;
 	t->queued = true;
 	t->running = running;
@@ -175,6 +178,16 @@ void runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running
 	runqueue_start_next(q);
 }
 
+void runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running)
+{
+	_runqueue_task_add(q, t, running, 0);
+}
+
+void runqueue_task_add_first(struct runqueue *q, struct runqueue_task *t, bool running)
+{
+	_runqueue_task_add(q, t, running, 1);
+}
+
 void runqueue_task_kill(struct runqueue_task *t)
 {
 	struct runqueue *q = t->q;

runqueue.h

@@ -100,6 +100,7 @@ void runqueue_stop(struct runqueue *q);
 void runqueue_resume(struct runqueue *q);
 
 void runqueue_task_add(struct runqueue *q, struct runqueue_task *t, bool running);
+void runqueue_task_add_first(struct runqueue *q, struct runqueue_task *t, bool running);
 void runqueue_task_complete(struct runqueue_task *t);
 
 void runqueue_task_cancel(struct runqueue_task *t, int type);

safe_list.c

@@ -86,6 +86,12 @@ void safe_list_add(struct safe_list *list, struct safe_list *head)
 	list_add_tail(&list->list, &head->list);
 }
 
+void safe_list_add_first(struct safe_list *list, struct safe_list *head)
+{
+	list->i = NULL;
+	list_add(&list->list, &head->list);
+}
+
 void safe_list_del(struct safe_list *list)
 {
 	struct safe_list_iterator *i, *next_i, **tail;

safe_list.h

@@ -42,6 +42,7 @@ int safe_list_for_each(struct safe_list *list,
 		       void *ctx);
 
 void safe_list_add(struct safe_list *list, struct safe_list *head);
+void safe_list_add_first(struct safe_list *list, struct safe_list *head);
 void safe_list_del(struct safe_list *list);
 
 #define INIT_SAFE_LIST(_head) \