percpu_ref: release percpu memory early without PERCPU_REF_ALLOW_REINIT
Release percpu memory after finishing the switch to the atomic mode
if only PERCPU_REF_ALLOW_REINIT isn't set.
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 9877682..501b517 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -69,11 +69,14 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release,
return -ENOMEM;
ref->force_atomic = flags & PERCPU_REF_INIT_ATOMIC;
+ ref->allow_reinit = flags & PERCPU_REF_ALLOW_REINIT;
- if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD))
+ if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD)) {
ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC;
- else
+ ref->allow_reinit = true;
+ } else {
start_count += PERCPU_COUNT_BIAS;
+ }
if (flags & PERCPU_REF_INIT_DEAD)
ref->percpu_count_ptr |= __PERCPU_REF_DEAD;
@@ -119,6 +122,9 @@ static void percpu_ref_call_confirm_rcu(struct rcu_head *rcu)
ref->confirm_switch = NULL;
wake_up_all(&percpu_ref_switch_waitq);
+ if (!ref->allow_reinit)
+ percpu_ref_exit(ref);
+
/* drop ref from percpu_ref_switch_to_atomic() */
percpu_ref_put(ref);
}
@@ -194,6 +200,9 @@ static void __percpu_ref_switch_to_percpu(struct percpu_ref *ref)
if (!(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC))
return;
+ if (WARN_ON_ONCE(!ref->allow_reinit))
+ return;
+
atomic_long_add(PERCPU_COUNT_BIAS, &ref->count);
/*