1 files changed, 36 insertions, 2 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index dee48658805..77dabbf64b8 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -229,6 +229,16 @@ static inline void set_wq_data(struct work_struct *work,
 	atomic_long_set(&work->data, new);
 }
 
+/*
+ * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued.
+ */
+static inline void clear_wq_data(struct work_struct *work)
+{
+	unsigned long flags = *work_data_bits(work) &
+				(1UL << WORK_STRUCT_STATIC);
+	atomic_long_set(&work->data, flags);
+}
+
 static inline
 struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
 {
@@ -671,7 +681,7 @@ static int __cancel_work_timer(struct work_struct *work,
 		wait_on_work(work);
 	} while (unlikely(ret < 0));
 
-	work_clear_pending(work);
+	clear_wq_data(work);
 	return ret;
 }
 
@@ -774,7 +784,7 @@ void flush_delayed_work(struct delayed_work *dwork)
 {
 	if (del_timer_sync(&dwork->timer)) {
 		struct cpu_workqueue_struct *cwq;
-		cwq = wq_per_cpu(keventd_wq, get_cpu());
+		cwq = wq_per_cpu(get_wq_data(&dwork->work)->wq, get_cpu());
 		__queue_work(cwq, &dwork->work);
 		put_cpu();
 	}
@@ -845,6 +855,30 @@ int schedule_on_each_cpu(work_func_t func)
 	return 0;
 }
 
+/**
+ * flush_scheduled_work - ensure that any scheduled work has run to completion.
+ *
+ * Forces execution of the kernel-global workqueue and blocks until its
+ * completion.
+ *
+ * Think twice before calling this function!  It's very easy to get into
+ * trouble if you don't take great care.  Either of the following situations
+ * will lead to deadlock:
+ *
+ *	One of the work items currently on the workqueue needs to acquire
+ *	a lock held by your code or its caller.
+ *
+ *	Your code is running in the context of a work routine.
+ *
+ * They will be detected by lockdep when they occur, but the first might not
+ * occur very often.  It depends on what work items are on the workqueue and
+ * what locks they need, which you have no control over.
+ *
+ * In most situations flushing the entire workqueue is overkill; you merely
+ * need to know that a particular work item isn't queued and isn't running.
+ * In such cases you should use cancel_delayed_work_sync() or
+ * cancel_work_sync() instead.
+ */
 void flush_scheduled_work(void)
 {
 	flush_workqueue(keventd_wq);