Merge branches 'pm-cpufreq', 'pm-cpuidle', 'pm-devfreq', 'pm-opp' and 'pm-tools'

[linux-drm-fsl-dcu.git] / kernel / sched / completion.c

diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
index 607f852b4d04ab3b70379bf42528aa40e5f588c7..7052d3fd4e7bd87a29bd144cbca1086621040251 100644 (file)
--- a/kernel/sched/completion.c
+++ b/kernel/sched/completion.c
@@ -268,6 +268,15 @@ bool try_wait_for_completion(struct completion *x)
        unsigned long flags;
        int ret = 1;
 
+       /*
+        * Since x->done will need to be locked only
+        * in the non-blocking case, we check x->done
+        * first without taking the lock so we can
+        * return early in the blocking case.
+        */
+       if (!ACCESS_ONCE(x->done))
+               return 0;
+
        spin_lock_irqsave(&x->wait.lock, flags);
        if (!x->done)
                ret = 0;
@@ -288,13 +297,6 @@ EXPORT_SYMBOL(try_wait_for_completion);
  */
 bool completion_done(struct completion *x)
 {
-       unsigned long flags;
-       int ret = 1;
-
-       spin_lock_irqsave(&x->wait.lock, flags);
-       if (!x->done)
-               ret = 0;
-       spin_unlock_irqrestore(&x->wait.lock, flags);
-       return ret;
+       return !!ACCESS_ONCE(x->done);
 }
 EXPORT_SYMBOL(completion_done);