timers: Fix slack calculation for expired timers

commit 3bbb9ec (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 <[email protected]> Cc: Arjan van de Ven <[email protected]>
mrcsosa · May 24, 2010 · f00e047 · f00e047
1 parent bd45b7a
commit f00e047
Showing 1 changed file with 4 additions and 3 deletions.
diff --git 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;