simplify cpu_hotplug_begin()/put_online_cpus()

[linux-2.6] / kernel / hrtimer.c

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 70d4adc74639f56b039f0dcfdacd7eda284784da..dea4c9124ac808b872d43a3dd83c15fc7cbb38a9 100644 (file)
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -590,7 +590,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
                        list_add_tail(&timer->cb_entry,
                                      &base->cpu_base->cb_pending);
                        timer->state = HRTIMER_STATE_PENDING;
-                       raise_softirq(HRTIMER_SOFTIRQ);
                        return 1;
                default:
                        BUG();
@@ -633,6 +632,11 @@ static int hrtimer_switch_to_hres(void)
        return 1;
 }
 
+static inline void hrtimer_raise_softirq(void)
+{
+       raise_softirq(HRTIMER_SOFTIRQ);
+}
+
 #else
 
 static inline int hrtimer_hres_active(void) { return 0; }
@@ -651,6 +655,7 @@ static inline int hrtimer_reprogram(struct hrtimer *timer,
 {
        return 0;
 }
+static inline void hrtimer_raise_softirq(void) { }
 
 #endif /* CONFIG_HIGH_RES_TIMERS */
 
@@ -850,7 +855,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
 {
        struct hrtimer_clock_base *base, *new_base;
        unsigned long flags;
-       int ret;
+       int ret, raise;
 
        base = lock_hrtimer_base(timer, &flags);
 
@@ -884,8 +889,18 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
        enqueue_hrtimer(timer, new_base,
                        new_base->cpu_base == &__get_cpu_var(hrtimer_bases));
 
+       /*
+        * The timer may be expired and moved to the cb_pending
+        * list. We can not raise the softirq with base lock held due
+        * to a possible deadlock with runqueue lock.
+        */
+       raise = timer->state == HRTIMER_STATE_PENDING;
+
        unlock_hrtimer_base(timer, &flags);
 
+       if (raise)
+               hrtimer_raise_softirq();
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(hrtimer_start);
@@ -1080,8 +1095,19 @@ static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
                         * If the timer was rearmed on another CPU, reprogram
                         * the event device.
                         */
-                       if (timer->base->first == &timer->node)
-                               hrtimer_reprogram(timer, timer->base);
+                       struct hrtimer_clock_base *base = timer->base;
+
+                       if (base->first == &timer->node &&
+                           hrtimer_reprogram(timer, base)) {
+                               /*
+                                * Timer is expired. Thus move it from tree to
+                                * pending list again.
+                                */
+                               __remove_hrtimer(timer, base,
+                                                HRTIMER_STATE_PENDING, 0);
+                               list_add_tail(&timer->cb_entry,
+                                             &base->cpu_base->cb_pending);
+                       }
                }
        }
        spin_unlock_irq(&cpu_base->lock);
@@ -1254,14 +1280,13 @@ void hrtimer_run_queues(void)
                if (!base->first)
                        continue;
 
-               if (gettime) {
+               if (base->get_softirq_time)
+                       base->softirq_time = base->get_softirq_time();
+               else if (gettime) {
                        hrtimer_get_softirq_time(cpu_base);
                        gettime = 0;
                }
 
-               if (base->get_softirq_time)
-                       base->softirq_time = base->get_softirq_time();
-
                spin_lock(&cpu_base->lock);
 
                while ((node = base->first)) {