struct request *elv_rb_former_request(struct request_queue *q,
				      struct request *rq)
{
	struct rb_node *rbprev = rb_prev(&rq->rb_node);

	if (rbprev)
		return rb_entry_rq(rbprev);

	return NULL;
}
struct request *elv_rb_former_request(struct request_queue *q,
				      struct request *rq)
{
	struct rb_node *rbprev = rb_prev(&rq->rb_node);

	if (rbprev)
		return rb_entry_rq(rbprev);

	return NULL;
}