1 files changed, 86 insertions, 17 deletions

diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 3d9f70972cd..d5dd4657c8d 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -16,24 +16,47 @@
 #ifdef CONFIG_SMP
 
 struct percpu_counter {
-	spinlock_t lock;
+	raw_spinlock_t lock;
 	s64 count;
 #ifdef CONFIG_HOTPLUG_CPU
 	struct list_head list;	/* All percpu_counters are on a list */
 #endif
-	s32 *counters;
+	s32 __percpu *counters;
 };
 
-#if NR_CPUS >= 16
-#define FBC_BATCH	(NR_CPUS*2)
-#else
-#define FBC_BATCH	(NR_CPUS*4)
-#endif
+extern int percpu_counter_batch;
+
+int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
+			  struct lock_class_key *key);
+
+#define percpu_counter_init(fbc, value)					\
+	({								\
+		static struct lock_class_key __key;			\
+									\
+		__percpu_counter_init(fbc, value, &__key);		\
+	})
 
-void percpu_counter_init(struct percpu_counter *fbc, s64 amount);
 void percpu_counter_destroy(struct percpu_counter *fbc);
-void percpu_counter_mod(struct percpu_counter *fbc, s32 amount);
-s64 percpu_counter_sum(struct percpu_counter *fbc);
+void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
+void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
+s64 __percpu_counter_sum(struct percpu_counter *fbc);
+int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs);
+
+static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
+{
+	__percpu_counter_add(fbc, amount, percpu_counter_batch);
+}
+
+static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
+{
+	s64 ret = __percpu_counter_sum(fbc);
+	return ret < 0 ? 0 : ret;
+}
+
+static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
+{
+	return __percpu_counter_sum(fbc);
+}
 
 static inline s64 percpu_counter_read(struct percpu_counter *fbc)
 {
@@ -52,57 +75,103 @@ static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
 	barrier();		/* Prevent reloads of fbc->count */
 	if (ret >= 0)
 		return ret;
-	return 1;
+	return 0;
+}
+
+static inline int percpu_counter_initialized(struct percpu_counter *fbc)
+{
+	return (fbc->counters != NULL);
 }
 
-#else
+#else /* !CONFIG_SMP */
 
 struct percpu_counter {
 	s64 count;
 };
 
-static inline void percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
 {
 	fbc->count = amount;
+	return 0;
 }
 
 static inline void percpu_counter_destroy(struct percpu_counter *fbc)
 {
 }
 
+static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
+{
+	fbc->count = amount;
+}
+
+static inline int percpu_counter_compare(struct percpu_counter *fbc, s64 rhs)
+{
+	if (fbc->count > rhs)
+		return 1;
+	else if (fbc->count < rhs)
+		return -1;
+	else
+		return 0;
+}
+
 static inline void
-percpu_counter_mod(struct percpu_counter *fbc, s32 amount)
+percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 {
 	preempt_disable();
 	fbc->count += amount;
 	preempt_enable();
 }
 
+static inline void
+__percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
+{
+	percpu_counter_add(fbc, amount);
+}
+
 static inline s64 percpu_counter_read(struct percpu_counter *fbc)
 {
 	return fbc->count;
 }
 
+/*
+ * percpu_counter is intended to track positive numbers. In the UP case the
+ * number should never be negative.
+ */
 static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
 {
 	return fbc->count;
 }
 
-static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
+static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
 {
 	return percpu_counter_read_positive(fbc);
 }
 
+static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
+{
+	return percpu_counter_read(fbc);
+}
+
+static inline int percpu_counter_initialized(struct percpu_counter *fbc)
+{
+	return 1;
+}
+
 #endif	/* CONFIG_SMP */
 
 static inline void percpu_counter_inc(struct percpu_counter *fbc)
 {
-	percpu_counter_mod(fbc, 1);
+	percpu_counter_add(fbc, 1);
 }
 
 static inline void percpu_counter_dec(struct percpu_counter *fbc)
 {
-	percpu_counter_mod(fbc, -1);
+	percpu_counter_add(fbc, -1);
+}
+
+static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount)
+{
+	percpu_counter_add(fbc, -amount);
 }
 
 #endif /* _LINUX_PERCPU_COUNTER_H */