Merge branch 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

[cascardo/linux.git] / include / linux / percpu-refcount.h

diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 51ce60c..b433764 100644 (file)
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -128,10 +128,8 @@ static inline void percpu_ref_kill(struct percpu_ref *ref)
 static inline bool __ref_is_percpu(struct percpu_ref *ref,
                                          unsigned long __percpu **percpu_countp)
 {
-       unsigned long percpu_ptr = ACCESS_ONCE(ref->percpu_count_ptr);
-
        /* paired with smp_store_release() in percpu_ref_reinit() */
-       smp_read_barrier_depends();
+       unsigned long percpu_ptr = lockless_dereference(ref->percpu_count_ptr);
 
        /*
         * Theoretically, the following could test just ATOMIC; however,
@@ -147,27 +145,41 @@ static inline bool __ref_is_percpu(struct percpu_ref *ref,
 }
 
 /**
- * percpu_ref_get - increment a percpu refcount
+ * percpu_ref_get_many - increment a percpu refcount
  * @ref: percpu_ref to get
+ * @nr: number of references to get
  *
- * Analagous to atomic_long_inc().
+ * Analogous to atomic_long_add().
  *
  * This function is safe to call as long as @ref is between init and exit.
  */
-static inline void percpu_ref_get(struct percpu_ref *ref)
+static inline void percpu_ref_get_many(struct percpu_ref *ref, unsigned long nr)
 {
        unsigned long __percpu *percpu_count;
 
        rcu_read_lock_sched();
 
        if (__ref_is_percpu(ref, &percpu_count))
-               this_cpu_inc(*percpu_count);
+               this_cpu_add(*percpu_count, nr);
        else
-               atomic_long_inc(&ref->count);
+               atomic_long_add(nr, &ref->count);
 
        rcu_read_unlock_sched();
 }
 
+/**
+ * percpu_ref_get - increment a percpu refcount
+ * @ref: percpu_ref to get
+ *
+ * Analagous to atomic_long_inc().
+ *
+ * This function is safe to call as long as @ref is between init and exit.
+ */
+static inline void percpu_ref_get(struct percpu_ref *ref)
+{
+       percpu_ref_get_many(ref, 1);
+}
+
 /**
  * percpu_ref_tryget - try to increment a percpu refcount
  * @ref: percpu_ref to try-get
@@ -231,28 +243,43 @@ static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
 }
 
 /**
- * percpu_ref_put - decrement a percpu refcount
+ * percpu_ref_put_many - decrement a percpu refcount
  * @ref: percpu_ref to put
+ * @nr: number of references to put
  *
  * Decrement the refcount, and if 0, call the release function (which was passed
  * to percpu_ref_init())
  *
  * This function is safe to call as long as @ref is between init and exit.
  */
-static inline void percpu_ref_put(struct percpu_ref *ref)
+static inline void percpu_ref_put_many(struct percpu_ref *ref, unsigned long nr)
 {
        unsigned long __percpu *percpu_count;
 
        rcu_read_lock_sched();
 
        if (__ref_is_percpu(ref, &percpu_count))
-               this_cpu_dec(*percpu_count);
-       else if (unlikely(atomic_long_dec_and_test(&ref->count)))
+               this_cpu_sub(*percpu_count, nr);
+       else if (unlikely(atomic_long_sub_and_test(nr, &ref->count)))
                ref->release(ref);
 
        rcu_read_unlock_sched();
 }
 
+/**
+ * percpu_ref_put - decrement a percpu refcount
+ * @ref: percpu_ref to put
+ *
+ * Decrement the refcount, and if 0, call the release function (which was passed
+ * to percpu_ref_init())
+ *
+ * This function is safe to call as long as @ref is between init and exit.
+ */
+static inline void percpu_ref_put(struct percpu_ref *ref)
+{
+       percpu_ref_put_many(ref, 1);
+}
+
 /**
  * percpu_ref_is_zero - test whether a percpu refcount reached zero
  * @ref: percpu_ref to test