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);
- if (unlikely(percpu_ptr & __PERCPU_REF_ATOMIC))
+ /*
+ * Theoretically, the following could test just ATOMIC; however,
+ * then we'd have to mask off DEAD separately as DEAD may be
+ * visible without ATOMIC if we race with percpu_ref_kill(). DEAD
+ * implies ATOMIC anyway. Test them together.
+ */
+ if (unlikely(percpu_ptr & __PERCPU_REF_ATOMIC_DEAD))
return false;
*percpu_countp = (unsigned long __percpu *)percpu_ptr;