kref: Implement kref_get_unless_zero v3

	}

	return 0;

}

/**

 * kref_get_unless_zero - Increment refcount for object unless it is zero.

 * @kref: object.

 *

 * Return non-zero if the increment succeeded. Otherwise return 0.

 *

 * This function is intended to simplify locking around refcounting for

 * objects that can be looked up from a lookup structure, and which are

 * removed from that lookup structure in the object destructor.

 * Operations on such objects require at least a read lock around

 * lookup + kref_get, and a write lock around kref_put + remove from lookup

 * structure. Furthermore, RCU implementations become extremely tricky.

 * With a lookup followed by a kref_get_unless_zero *with return value check*

 * locking in the kref_put path can be deferred to the actual removal from

 * the lookup structure and RCU lookups become trivial.

 */

static inline int __must_check kref_get_unless_zero(struct kref *kref)

{

	return atomic_add_unless(&kref->refcount, 1, 0);

}

#endif /* _KREF_H_ */