Merge commit 'v2.6.28-rc6' into core/debug

[safe/jmp/linux-2.6] / lib / percpu_counter.c

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index f736d67..a866389 100644 (file)
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -14,9 +14,23 @@ static LIST_HEAD(percpu_counters);
 static DEFINE_MUTEX(percpu_counters_lock);
 #endif
 
-void __percpu_counter_add(struct percpu_counter *fbc, s32 amount, s32 batch)
+void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
 {
-       long count;
+       int cpu;
+
+       spin_lock(&fbc->lock);
+       for_each_possible_cpu(cpu) {
+               s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
+               *pcount = 0;
+       }
+       fbc->count = amount;
+       spin_unlock(&fbc->lock);
+}
+EXPORT_SYMBOL(percpu_counter_set);
+
+void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
+{
+       s64 count;
        s32 *pcount;
        int cpu = get_cpu();
 
@@ -38,7 +52,7 @@ EXPORT_SYMBOL(__percpu_counter_add);
  * Add up all the per-cpu counts, return the result.  This is a more accurate
  * but much slower version of percpu_counter_read_positive()
  */
-s64 percpu_counter_sum(struct percpu_counter *fbc)
+s64 __percpu_counter_sum(struct percpu_counter *fbc)
 {
        s64 ret;
        int cpu;
@@ -48,28 +62,50 @@ s64 percpu_counter_sum(struct percpu_counter *fbc)
        for_each_online_cpu(cpu) {
                s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
                ret += *pcount;
+               *pcount = 0;
        }
+       fbc->count = ret;
+
        spin_unlock(&fbc->lock);
-       return ret < 0 ? 0 : ret;
+       return ret;
 }
-EXPORT_SYMBOL(percpu_counter_sum);
+EXPORT_SYMBOL(__percpu_counter_sum);
+
+static struct lock_class_key percpu_counter_irqsafe;
 
-void percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
 {
        spin_lock_init(&fbc->lock);
        fbc->count = amount;
        fbc->counters = alloc_percpu(s32);
+       if (!fbc->counters)
+               return -ENOMEM;
 #ifdef CONFIG_HOTPLUG_CPU
        mutex_lock(&percpu_counters_lock);
        list_add(&fbc->list, &percpu_counters);
        mutex_unlock(&percpu_counters_lock);
 #endif
+       return 0;
 }
 EXPORT_SYMBOL(percpu_counter_init);
 
+int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount)
+{
+       int err;
+
+       err = percpu_counter_init(fbc, amount);
+       if (!err)
+               lockdep_set_class(&fbc->lock, &percpu_counter_irqsafe);
+       return err;
+}
+
 void percpu_counter_destroy(struct percpu_counter *fbc)
 {
+       if (!fbc->counters)
+               return;
+
        free_percpu(fbc->counters);
+       fbc->counters = NULL;
 #ifdef CONFIG_HOTPLUG_CPU
        mutex_lock(&percpu_counters_lock);
        list_del(&fbc->list);
@@ -92,12 +128,13 @@ static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
        mutex_lock(&percpu_counters_lock);
        list_for_each_entry(fbc, &percpu_counters, list) {
                s32 *pcount;
+               unsigned long flags;
 
-               spin_lock(&fbc->lock);
+               spin_lock_irqsave(&fbc->lock, flags);
                pcount = per_cpu_ptr(fbc->counters, cpu);
                fbc->count += *pcount;
                *pcount = 0;
-               spin_unlock(&fbc->lock);
+               spin_unlock_irqrestore(&fbc->lock, flags);
        }
        mutex_unlock(&percpu_counters_lock);
        return NOTIFY_OK;