workqueue: make rescuer_thread() empty wq->maydays list before exiting

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 8b5ef62..b6a3941 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2397,6 +2397,7 @@ static int rescuer_thread(void *__rescuer)
        struct worker *rescuer = __rescuer;
        struct workqueue_struct *wq = rescuer->rescue_wq;
        struct list_head *scheduled = &rescuer->scheduled;
+       bool should_stop;
 
        set_user_nice(current, RESCUER_NICE_LEVEL);
 
@@ -2408,11 +2409,15 @@ static int rescuer_thread(void *__rescuer)
 repeat:
        set_current_state(TASK_INTERRUPTIBLE);
 
-       if (kthread_should_stop()) {
-               __set_current_state(TASK_RUNNING);
-               rescuer->task->flags &= ~PF_WQ_WORKER;
-               return 0;
-       }
+       /*
+        * By the time the rescuer is requested to stop, the workqueue
+        * shouldn't have any work pending, but @wq->maydays may still have
+        * pwq(s) queued.  This can happen by non-rescuer workers consuming
+        * all the work items before the rescuer got to them.  Go through
+        * @wq->maydays processing before acting on should_stop so that the
+        * list is always empty on exit.
+        */
+       should_stop = kthread_should_stop();
 
        /* see whether any pwq is asking for help */
        spin_lock_irq(&wq_mayday_lock);
@@ -2464,6 +2469,12 @@ repeat:
 
        spin_unlock_irq(&wq_mayday_lock);
 
+       if (should_stop) {
+               __set_current_state(TASK_RUNNING);
+               rescuer->task->flags &= ~PF_WQ_WORKER;
+               return 0;
+       }
+
        /* rescuers should never participate in concurrency management */
        WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
        schedule();