[PATCH] USB: Improve Kconfig comment for mct_u232

[powerpc.git] / kernel / timer.c

diff --git a/kernel/timer.c b/kernel/timer.c
index 67eaf0f..9e49dee 100644 (file)
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -541,6 +541,22 @@ found:
        }
        spin_unlock(&base->lock);
 
+       /*
+        * It can happen that other CPUs service timer IRQs and increment
+        * jiffies, but we have not yet got a local timer tick to process
+        * the timer wheels.  In that case, the expiry time can be before
+        * jiffies, but since the high-resolution timer here is relative to
+        * jiffies, the default expression when high-resolution timers are
+        * not active,
+        *
+        *   time_before(MAX_JIFFY_OFFSET + jiffies, expires)
+        *
+        * would falsely evaluate to true.  If that is the case, just
+        * return jiffies so that we can immediately fire the local timer
+        */
+       if (time_before(expires, jiffies))
+               return jiffies;
+
        if (time_before(hr_expires, expires))
                return hr_expires;