diff --git a/include/linux/kref.h b/include/linux/kref.h index 6cc38fc07ab76c5a052d530eec2fd31ec4d25392..90b9e44abf54aa5c346524e4306b6695b9fca980 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -23,6 +23,7 @@ struct kref { void kref_init(struct kref *kref); void kref_get(struct kref *kref); +int kref_test_and_get(struct kref *kref); int kref_put(struct kref *kref, void (*release) (struct kref *kref)); #endif /* _KREF_H_ */ diff --git a/lib/kref.c b/lib/kref.c index d3d227a08a4bdb79cae0b2f21be905451c607719..e7a6e106712231ba43b0aa426bcfd003ce8409a7 100644 --- a/lib/kref.c +++ b/lib/kref.c @@ -36,6 +36,18 @@ void kref_get(struct kref *kref) smp_mb__after_atomic_inc(); } +/** + * kref_test_and_get - increment refcount for object only if refcount is not + * zero. + * @kref: object. + * + * Return non-zero if the refcount was incremented, 0 otherwise + */ +int kref_test_and_get(struct kref *kref) +{ + return atomic_inc_not_zero(&kref->refcount); +} + /** * kref_put - decrement refcount for object. * @kref: object.