register_vt_notifier
register_vt_notifier(&vt_notifier_block);
err = register_vt_notifier(&vt_notifier_block);
if (register_vt_notifier(&poll->notifier) != 0) {
EXPORT_SYMBOL_GPL(register_vt_notifier);
int register_vt_notifier(struct notifier_block *nb);