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>

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>
Jeff Chua · Thomas Gleixner
1 parent bd45b7a385
Showing 1 changed file with 4 additions and 3 deletions Side-by-side Diff
kernel/timer.c
@@ -750,13 +750,14 @@
 	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;
...	...	@@ -750,13 +750,14 @@
750	750	unsigned long expires_limit, mask;
751	751	int bit;
752	752
753		- expires_limit = expires + timer->slack;
	753	+ expires_limit = expires;
754	754
755		- if (timer->slack < 0) /* auto slack: use 0.4% */
	755	+ if (timer->slack > -1)
	756	+ expires_limit = expires + timer->slack;
	757	+ else if (time_after(expires, jiffies)) /* auto slack: use 0.4% */
756	758	expires_limit = expires + (expires - jiffies)/256;
757	759
758	760	mask = expires ^ expires_limit;
759		-
760	761	if (mask == 0)
761	762	return expires;
762	763