workqueue: add cancel_work()

Like cancel_delayed_work(), but for regular work.

Signed-off-by: Jens Axboe <axboe@fb.com>
Mehed-by: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index ef071ca..bd81f03 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2974,6 +2974,31 @@
 }
 EXPORT_SYMBOL(flush_delayed_work);
 
+static bool __cancel_work(struct work_struct *work, bool is_dwork)
+{
+	unsigned long flags;
+	int ret;
+
+	do {
+		ret = try_to_grab_pending(work, is_dwork, &flags);
+	} while (unlikely(ret == -EAGAIN));
+
+	if (unlikely(ret < 0))
+		return false;
+
+	set_work_pool_and_clear_pending(work, get_work_pool_id(work));
+	local_irq_restore(flags);
+	return ret;
+}
+
+/*
+ * See cancel_delayed_work()
+ */
+bool cancel_work(struct work_struct *work)
+{
+	return __cancel_work(work, false);
+}
+
 /**
  * cancel_delayed_work - cancel a delayed work
  * @dwork: delayed_work to cancel
@@ -2992,20 +3017,7 @@
  */
 bool cancel_delayed_work(struct delayed_work *dwork)
 {
-	unsigned long flags;
-	int ret;
-
-	do {
-		ret = try_to_grab_pending(&dwork->work, true, &flags);
-	} while (unlikely(ret == -EAGAIN));
-
-	if (unlikely(ret < 0))
-		return false;
-
-	set_work_pool_and_clear_pending(&dwork->work,
-					get_work_pool_id(&dwork->work));
-	local_irq_restore(flags);
-	return ret;
+	return __cancel_work(&dwork->work, true);
 }
 EXPORT_SYMBOL(cancel_delayed_work);