diff --git a/include/linux/rcuref.h b/include/linux/rcuref.h index 2c8bfd0f1b6b3a..6322d8c1c6b429 100644 --- a/include/linux/rcuref.h +++ b/include/linux/rcuref.h @@ -71,27 +71,30 @@ static inline __must_check bool rcuref_get(rcuref_t *ref) return rcuref_get_slowpath(ref); } -extern __must_check bool rcuref_put_slowpath(rcuref_t *ref); +extern __must_check bool rcuref_put_slowpath(rcuref_t *ref, unsigned int cnt); /* * Internal helper. Do not invoke directly. */ static __always_inline __must_check bool __rcuref_put(rcuref_t *ref) { + int cnt; + RCU_LOCKDEP_WARN(!rcu_read_lock_held() && preemptible(), "suspicious rcuref_put_rcusafe() usage"); /* * Unconditionally decrease the reference count. The saturation and * dead zones provide enough tolerance for this. */ - if (likely(!atomic_add_negative_release(-1, &ref->refcnt))) + cnt = atomic_sub_return_release(1, &ref->refcnt); + if (likely(cnt >= 0)) return false; /* * Handle the last reference drop and cases inside the saturation * and dead zones. */ - return rcuref_put_slowpath(ref); + return rcuref_put_slowpath(ref, cnt); } /** diff --git a/lib/rcuref.c b/lib/rcuref.c index 97f300eca927ce..5bd726b71e3936 100644 --- a/lib/rcuref.c +++ b/lib/rcuref.c @@ -220,6 +220,7 @@ EXPORT_SYMBOL_GPL(rcuref_get_slowpath); /** * rcuref_put_slowpath - Slowpath of __rcuref_put() * @ref: Pointer to the reference count + * @cnt: The resulting value of the fastpath decrement * * Invoked when the reference count is outside of the valid zone. * @@ -233,10 +234,8 @@ EXPORT_SYMBOL_GPL(rcuref_get_slowpath); * with a concurrent get()/put() pair. Caller is not allowed to * deconstruct the protected object. */ -bool rcuref_put_slowpath(rcuref_t *ref) +bool rcuref_put_slowpath(rcuref_t *ref, unsigned int cnt) { - unsigned int cnt = atomic_read(&ref->refcnt); - /* Did this drop the last reference? */ if (likely(cnt == RCUREF_NOREF)) { /*