* closes the eventfd or on cgroup removing.
* This callback must be implemented, if you want provide
* notification functionality.
- *
- * Be careful. It can be called after destroy(), so you have
- * to keep all nesessary data, until all events are removed.
*/
int (*unregister_event)(struct cgroup *cgrp, struct cftype *cft,
struct eventfd_ctx *eventfd);