git » linux-kernel » commit f00e047

timers: Fix slack calculation for expired timers

author Jeff Chua
2010-05-23 23:16:24 UTC
committer Thomas Gleixner
2010-05-24 10:10:23 UTC
parent bd45b7a385c5ffd82c11a1d51880be18559e5ad9
timers: Fix slack calculation for expired timers

commit 3bbb9ec946 (timers: Introduce the concept of timer slack for
legacy timers) does not take the case into account when the timer is
already expired. This broke wireless drivers.

The solution is not to apply slack to already expired timers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
kernel/timer.c +4 -3 
diff --git a/kernel/timer.c b/kernel/timer.c
index 9199f3c5221..be394af5bc2 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -750,13 +750,14 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
 	unsigned long expires_limit, mask;
 	int bit;
 
-	expires_limit = expires + timer->slack;
+	expires_limit = expires;
 
-	if (timer->slack < 0) /* auto slack: use 0.4% */
+	if (timer->slack > -1)
+		expires_limit = expires + timer->slack;
+	else if (time_after(expires, jiffies)) /* auto slack: use 0.4% */
 		expires_limit = expires + (expires - jiffies)/256;
 
 	mask = expires ^ expires_limit;
-
 	if (mask == 0)
 		return expires;