clocksource: Simplify clocksource watchdog resume logic

To resume the clocksource watchdog just remove the CLOCK_SOURCE_WATCHDOG
bit from the watched clocksource.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
LKML-Reference: <20090814134808.880925790@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 76256c5..89a7b91 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -145,7 +145,6 @@ static struct clocksource *watchdog;
 static struct timer_list watchdog_timer;
 static DEFINE_SPINLOCK(watchdog_lock);
 static cycle_t watchdog_last;
-static unsigned long watchdog_resumed;
 
 /*
  * Interval: 0.5sec Threshold: 0.0625s
@@ -167,12 +166,9 @@ static void clocksource_watchdog(unsigned long data)
        struct clocksource *cs, *tmp;
        cycle_t csnow, wdnow;
        int64_t wd_nsec, cs_nsec;
-       int resumed;
 
        spin_lock(&watchdog_lock);
 
-       resumed = test_and_clear_bit(0, &watchdog_resumed);
-
        wdnow = watchdog->read(watchdog);
        wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask);
        watchdog_last = wdnow;
@@ -223,14 +219,26 @@ static void clocksource_watchdog(unsigned long data)
        }
        spin_unlock(&watchdog_lock);
 }
+
+static inline void clocksource_reset_watchdog(void)
+{
+       struct clocksource *cs;
+
+       list_for_each_entry(cs, &watchdog_list, wd_list)
+               cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
+}
+
 static void clocksource_resume_watchdog(void)
 {
-       set_bit(0, &watchdog_resumed);
+       unsigned long flags;
+
+       spin_lock_irqsave(&watchdog_lock, flags);
+       clocksource_reset_watchdog();
+       spin_unlock_irqrestore(&watchdog_lock, flags);
 }
 
 static void clocksource_check_watchdog(struct clocksource *cs)
 {
-       struct clocksource *cse;
        unsigned long flags;
 
        spin_lock_irqsave(&watchdog_lock, flags);
@@ -256,8 +264,7 @@ static void clocksource_check_watchdog(struct clocksource *cs)
                        watchdog_timer.function = clocksource_watchdog;
 
                        /* Reset watchdog cycles */
-                       list_for_each_entry(cse, &watchdog_list, wd_list)
-                               cse->flags &= ~CLOCK_SOURCE_WATCHDOG;
+                       clocksource_reset_watchdog();
                        /* Start if list is not empty */
                        if (!list_empty(&watchdog_list)) {
                                watchdog_last = watchdog->read(watchdog);