clocksource: Make watchdog robust vs. interruption

[karo-tx-linux.git] / kernel / time / clocksource.c

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c232eebbf7ee3ee4a8257d53edfcd0a860b60a6f..4db1e0adc7d7cd1c12e8c2c377ea33ac1035ae87 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -184,7 +184,6 @@ static struct clocksource *watchdog;
 static struct timer_list watchdog_timer;
 static DECLARE_WORK(watchdog_work, clocksource_watchdog_work);
 static DEFINE_SPINLOCK(watchdog_lock);
-static cycle_t watchdog_last;
 static int watchdog_running;
 
 static int clocksource_watchdog_kthread(void *data);
@@ -253,11 +252,6 @@ static void clocksource_watchdog(unsigned long data)
        if (!watchdog_running)
                goto out;
 
-       wdnow = watchdog->read(watchdog);
-       wd_nsec = clocksource_cyc2ns((wdnow - watchdog_last) & watchdog->mask,
-                                    watchdog->mult, watchdog->shift);
-       watchdog_last = wdnow;
-
        list_for_each_entry(cs, &watchdog_list, wd_list) {
 
                /* Clocksource already marked unstable? */
@@ -267,19 +261,28 @@ static void clocksource_watchdog(unsigned long data)
                        continue;
                }
 
+               local_irq_disable();
                csnow = cs->read(cs);
+               wdnow = watchdog->read(watchdog);
+               local_irq_enable();
 
                /* Clocksource initialized ? */
                if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
                        cs->flags |= CLOCK_SOURCE_WATCHDOG;
-                       cs->wd_last = csnow;
+                       cs->wd_last = wdnow;
+                       cs->cs_last = csnow;
                        continue;
                }
 
-               /* Check the deviation from the watchdog clocksource. */
-               cs_nsec = clocksource_cyc2ns((csnow - cs->wd_last) &
+               wd_nsec = clocksource_cyc2ns((wdnow - cs->wd_last) & watchdog->mask,
+                                            watchdog->mult, watchdog->shift);
+
+               cs_nsec = clocksource_cyc2ns((csnow - cs->cs_last) &
                                             cs->mask, cs->mult, cs->shift);
-               cs->wd_last = csnow;
+               cs->cs_last = csnow;
+               cs->wd_last = wdnow;
+
+               /* Check the deviation from the watchdog clocksource. */
                if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
                        clocksource_unstable(cs, cs_nsec - wd_nsec);
                        continue;
@@ -317,7 +320,6 @@ static inline void clocksource_start_watchdog(void)
                return;
        init_timer(&watchdog_timer);
        watchdog_timer.function = clocksource_watchdog;
-       watchdog_last = watchdog->read(watchdog);
        watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
        add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask));
        watchdog_running = 1;