sched: fix wait_for_completion_timeout() spurious failure under heavy load

[cascardo/linux.git] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index 4a3cb06..577f160 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4405,6 +4405,16 @@ do_wait_for_common(struct completion *x, long timeout, int state)
                        spin_unlock_irq(&x->wait.lock);
                        timeout = schedule_timeout(timeout);
                        spin_lock_irq(&x->wait.lock);
+
+                       /*
+                        * If the completion has arrived meanwhile
+                        * then return 1 jiffy time left:
+                        */
+                       if (x->done && !timeout) {
+                               timeout = 1;
+                               break;
+                       }
+
                        if (!timeout) {
                                __remove_wait_queue(&x->wait, &wait);
                                return timeout;