int add_random_ready_callback(struct random_ready_callback *rdy)
{
	struct module *owner;
	unsigned long flags;
	int err = -EALREADY;

	if (crng_ready())
		return err;

	owner = rdy->owner;
	if (!try_module_get(owner))
		return -ENOENT;

	spin_lock_irqsave(&random_ready_list_lock, flags);
	if (crng_ready())
		goto out;

	owner = NULL;

	list_add(&rdy->list, &random_ready_list);
	err = 0;

out:
	spin_unlock_irqrestore(&random_ready_list_lock, flags);

	module_put(owner);

	return err;
}