workqueue: factor out __queue_delayed_work() from queue_delayed_work_on()

This is to prepare for mod_delayed_work[_on]() and doesn't cause any
functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/workqueue.c

@@ -1261,32 +1261,11 @@ void delayed_work_timer_fn(unsigned long __data)
 }
 EXPORT_SYMBOL_GPL(delayed_work_timer_fn);
 
-/**
- * queue_delayed_work_on - queue work on specific CPU after delay
- * @cpu: CPU number to execute work on
- * @wq: workqueue to use
- * @dwork: work to queue
- * @delay: number of jiffies to wait before queueing
- *
- * Returns %false if @work was already on a queue, %true otherwise.  If
- * @delay is zero and @dwork is idle, it will be scheduled for immediate
- * execution.
- */
-bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
+static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
 				struct delayed_work *dwork, unsigned long delay)
 {
 	struct timer_list *timer = &dwork->timer;
 	struct work_struct *work = &dwork->work;
-	bool ret = false;
-	unsigned long flags;
-
-	if (!delay)
-		return queue_work_on(cpu, wq, &dwork->work);
-
-	/* read the comment in __queue_work() */
-	local_irq_save(flags);
-
-	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
 	unsigned int lcpu;
 
 	WARN_ON_ONCE(timer->function != delayed_work_timer_fn ||
@@ -1297,9 +1276,9 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 	timer_stats_timer_set_start_info(&dwork->timer);
 
 	/*
-		 * This stores cwq for the moment, for the timer_fn.
-		 * Note that the work's gcwq is preserved to allow
-		 * reentrance detection for delayed works.
+	 * This stores cwq for the moment, for the timer_fn.  Note that the
+	 * work's gcwq is preserved to allow reentrance detection for
+	 * delayed works.
 	 */
 	if (!(wq->flags & WQ_UNBOUND)) {
 		struct global_cwq *gcwq = get_work_gcwq(work);
@@ -1308,8 +1287,9 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 			lcpu = gcwq->cpu;
 		else
 			lcpu = raw_smp_processor_id();
-		} else
+	} else {
 		lcpu = WORK_CPU_UNBOUND;
+	}
 
 	set_work_cwq(work, get_cwq(lcpu, wq), 0);
 
@@ -1319,6 +1299,34 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 		add_timer_on(timer, cpu);
 	else
 		add_timer(timer);
+}
+
+/**
+ * queue_delayed_work_on - queue work on specific CPU after delay
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @dwork: work to queue
+ * @delay: number of jiffies to wait before queueing
+ *
+ * Returns %false if @work was already on a queue, %true otherwise.  If
+ * @delay is zero and @dwork is idle, it will be scheduled for immediate
+ * execution.
+ */
+bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
+			   struct delayed_work *dwork, unsigned long delay)
+{
+	struct work_struct *work = &dwork->work;
+	bool ret = false;
+	unsigned long flags;
+
+	if (!delay)
+		return queue_work_on(cpu, wq, &dwork->work);
+
+	/* read the comment in __queue_work() */
+	local_irq_save(flags);
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		__queue_delayed_work(cpu, wq, dwork, delay);
 		ret = true;
 	}