1 files changed, 40 insertions, 8 deletions

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index cf22c617baa4..9659eabffc31 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);