Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[mirror_ubuntu-artful-kernel.git] / include / linux / percpu-refcount.h

diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 84f542df7ff5cca0932f02b6629f8229244c2d1a..1c7eec09e5eba7ae8c0cc8e82172791f992bb361 100644 (file)
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -136,14 +136,12 @@ static inline bool __ref_is_percpu(struct percpu_ref *ref,
         * used as a pointer.  If the compiler generates a separate fetch
         * when using it as a pointer, __PERCPU_REF_ATOMIC may be set in
         * between contaminating the pointer value, meaning that
-        * ACCESS_ONCE() is required when fetching it.
-        *
-        * Also, we need a data dependency barrier to be paired with
-        * smp_store_release() in __percpu_ref_switch_to_percpu().
-        *
-        * Use lockless deref which contains both.
+        * READ_ONCE() is required when fetching it.
         */
-       percpu_ptr = lockless_dereference(ref->percpu_count_ptr);
+       percpu_ptr = READ_ONCE(ref->percpu_count_ptr);
+
+       /* paired with smp_store_release() in __percpu_ref_switch_to_percpu() */
+       smp_read_barrier_depends();
 
        /*
         * Theoretically, the following could test just ATOMIC; however,