1 files changed, 40 insertions, 8 deletions

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index cf22c617baa..9659eabffc3 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -14,15 +14,29 @@ static LIST_HEAD(percpu_counters);
 static DEFINE_MUTEX(percpu_counters_lock);
 #endif
 
-void percpu_counter_mod(struct percpu_counter *fbc, s32 amount)
+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();
 
 	pcount = per_cpu_ptr(fbc->counters, cpu);
 	count = *pcount + amount;
-	if (count >= FBC_BATCH || count <= -FBC_BATCH) {
+	if (count >= batch || count <= -batch) {
 		spin_lock(&fbc->lock);
 		fbc->count += count;
 		*pcount = 0;
@@ -32,13 +46,13 @@ void percpu_counter_mod(struct percpu_counter *fbc, s32 amount)
 	}
 	put_cpu();
 }
-EXPORT_SYMBOL(percpu_counter_mod);
+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;
@@ -50,25 +64,43 @@ s64 percpu_counter_sum(struct percpu_counter *fbc)
 		ret += *pcount;
 	}
 	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);
 #ifdef CONFIG_HOTPLUG_CPU
 	mutex_lock(&percpu_counters_lock);