Merge tag 'v3.16-rc5' into next/fixes-non-critical

Linux 3.16-rc5

1 files changed, 36 insertions, 4 deletions

diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 95961f0bf62d..5d8920e23073 100644
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -110,7 +110,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
         pcpu_count = ACCESS_ONCE(ref->pcpu_count);
 
         if (likely(REF_STATUS(pcpu_count) == PCPU_REF_PTR))
-                __this_cpu_inc(*pcpu_count);
+                this_cpu_inc(*pcpu_count);
         else
                 atomic_inc(&ref->count);
 
@@ -121,6 +121,36 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
  * percpu_ref_tryget - try to increment a percpu refcount
  * @ref: percpu_ref to try-get
  *
+ * Increment a percpu refcount unless its count already reached zero.
+ * Returns %true on success; %false on failure.
+ *
+ * The caller is responsible for ensuring that @ref stays accessible.
+ */
+static inline bool percpu_ref_tryget(struct percpu_ref *ref)
+{
+        unsigned __percpu *pcpu_count;
+        int ret = false;
+
+        rcu_read_lock_sched();
+
+        pcpu_count = ACCESS_ONCE(ref->pcpu_count);
+
+        if (likely(REF_STATUS(pcpu_count) == PCPU_REF_PTR)) {
+                this_cpu_inc(*pcpu_count);
+                ret = true;
+        } else {
+                ret = atomic_inc_not_zero(&ref->count);
+        }
+
+        rcu_read_unlock_sched();
+
+        return ret;
+}
+
+/**
+ * percpu_ref_tryget_live - try to increment a live percpu refcount
+ * @ref: percpu_ref to try-get
+ *
  * Increment a percpu refcount unless it has already been killed.  Returns
  * %true on success; %false on failure.
  *
@@ -128,8 +158,10 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
  * will fail.  For such guarantee, percpu_ref_kill_and_confirm() should be
  * used.  After the confirm_kill callback is invoked, it's guaranteed that
  * no new reference will be given out by percpu_ref_tryget().
+ *
+ * The caller is responsible for ensuring that @ref stays accessible.
  */
-static inline bool percpu_ref_tryget(struct percpu_ref *ref)
+static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)
 {
         unsigned __percpu *pcpu_count;
         int ret = false;
@@ -139,7 +171,7 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref)
         pcpu_count = ACCESS_ONCE(ref->pcpu_count);
 
         if (likely(REF_STATUS(pcpu_count) == PCPU_REF_PTR)) {
-                __this_cpu_inc(*pcpu_count);
+                this_cpu_inc(*pcpu_count);
                 ret = true;
         }
 
@@ -164,7 +196,7 @@ static inline void percpu_ref_put(struct percpu_ref *ref)
         pcpu_count = ACCESS_ONCE(ref->pcpu_count);
 
         if (likely(REF_STATUS(pcpu_count) == PCPU_REF_PTR))
-                __this_cpu_dec(*pcpu_count);
+                this_cpu_dec(*pcpu_count);
         else if (unlikely(atomic_dec_and_test(&ref->count)))
                 ref->release(ref);