clockevents: prevent endless loop in periodic broadcast handler

[pandora-kernel.git] / kernel / time / tick-broadcast.c

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 57a1f02..3044a88 100644 (file)
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -30,6 +30,7 @@
 struct tick_device tick_broadcast_device;
 static cpumask_t tick_broadcast_mask;
 static DEFINE_SPINLOCK(tick_broadcast_lock);
+static int tick_broadcast_force;
 
 #ifdef CONFIG_TICK_ONESHOT
 static void tick_broadcast_clear_oneshot(int cpu);
@@ -174,6 +175,8 @@ static void tick_do_periodic_broadcast(void)
  */
 static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 {
+       ktime_t next;
+
        tick_do_periodic_broadcast();
 
        /*
@@ -184,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 
        /*
         * Setup the next period for devices, which do not have
-        * periodic mode:
+        * periodic mode. We read dev->next_event first and add to it
+        * when the event alrady expired. clockevents_program_event()
+        * sets dev->next_event only when the event is really
+        * programmed to the device.
         */
-       for (;;) {
-               ktime_t next = ktime_add(dev->next_event, tick_period);
+       for (next = dev->next_event; ;) {
+               next = ktime_add(next, tick_period);
 
                if (!clockevents_program_event(dev, next, ktime_get()))
                        return;
@@ -232,10 +238,11 @@ static void tick_do_broadcast_on_off(void *why)
                                                     CLOCK_EVT_MODE_SHUTDOWN);
                }
                if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
-                       dev->features |= CLOCK_EVT_FEAT_DUMMY;
+                       tick_broadcast_force = 1;
                break;
        case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
-               if (cpu_isset(cpu, tick_broadcast_mask)) {
+               if (!tick_broadcast_force &&
+                   cpu_isset(cpu, tick_broadcast_mask)) {
                        cpu_clear(cpu, tick_broadcast_mask);
                        if (td->mode == TICKDEV_MODE_PERIODIC)
                                tick_setup_periodic(dev, 0);
@@ -266,7 +273,7 @@ void tick_broadcast_on_off(unsigned long reason, int *oncpu)
                       "offline CPU #%d\n", *oncpu);
        else
                smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
-                                        &reason, 1, 1);
+                                        &reason, 1);
 }
 
 /*
@@ -397,8 +404,7 @@ again:
        mask = CPU_MASK_NONE;
        now = ktime_get();
        /* Find all expired events */
-       for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
-            cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
+       for_each_cpu_mask_nr(cpu, tick_broadcast_oneshot_mask) {
                td = &per_cpu(tick_cpu_device, cpu);
                if (td->evtdev->next_event.tv64 <= now.tv64)
                        cpu_set(cpu, mask);