diff options
| -rw-r--r-- | include/linux/kref.h | 9 | ||||
| -rw-r--r-- | lib/kobject.c | 2 |
2 files changed, 7 insertions, 4 deletions
diff --git a/include/linux/kref.h b/include/linux/kref.h index 4972e6e9ca9..e15828fd71f 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -39,8 +39,11 @@ static inline void kref_init(struct kref *kref) */ static inline void kref_get(struct kref *kref) { - WARN_ON(!atomic_read(&kref->refcount)); - atomic_inc(&kref->refcount); + /* If refcount was 0 before incrementing then we have a race + * condition when this kref is freeing by some other thread right now. + * In this case one should use kref_get_unless_zero() + */ + WARN_ON_ONCE(atomic_inc_return(&kref->refcount) < 2); } /** @@ -100,7 +103,7 @@ static inline int kref_put_mutex(struct kref *kref, struct mutex *lock) { WARN_ON(release == NULL); - if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) { + if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) { mutex_lock(lock); if (unlikely(!atomic_dec_and_test(&kref->refcount))) { mutex_unlock(lock); diff --git a/lib/kobject.c b/lib/kobject.c index a65486613d7..b7e29a6056d 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -529,7 +529,7 @@ struct kobject *kobject_get(struct kobject *kobj) return kobj; } -static struct kobject *kobject_get_unless_zero(struct kobject *kobj) +static struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj) { if (!kref_get_unless_zero(&kobj->kref)) kobj = NULL; |