Merge tag 'powerpc-4.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...

[cascardo/linux.git] / lib / percpu-refcount.c

diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index c69938e..9ac959e 100644 (file)
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -83,6 +83,7 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release,
        atomic_long_set(&ref->count, start_count);
 
        ref->release = release;
+       ref->confirm_switch = NULL;
        return 0;
 }
 EXPORT_SYMBOL_GPL(percpu_ref_init);
@@ -102,6 +103,8 @@ void percpu_ref_exit(struct percpu_ref *ref)
        unsigned long __percpu *percpu_count = percpu_count_ptr(ref);
 
        if (percpu_count) {
+               /* non-NULL confirm_switch indicates switching in progress */
+               WARN_ON_ONCE(ref->confirm_switch);
                free_percpu(percpu_count);
                ref->percpu_count_ptr = __PERCPU_REF_ATOMIC_DEAD;
        }