
static struct request *bfq_find_next_rq(struct bfq_data *bfqd,
					struct bfq_queue *bfqq,
					struct request *last)
{
	struct rb_node *rbnext = rb_next(&last->rb_node);
	struct rb_node *rbprev = rb_prev(&last->rb_node);
	struct request *next, *prev = NULL;

	/* Follow expired path, else get first next available. */
	next = bfq_check_fifo(bfqq, last);
	if (next)
		return next;

	if (rbprev)
		prev = rb_entry_rq(rbprev);

	if (rbnext)
		next = rb_entry_rq(rbnext);
	else {
		rbnext = rb_first(&bfqq->sort_list);
		if (rbnext && rbnext != &last->rb_node)
			next = rb_entry_rq(rbnext);
	}

	return bfq_choose_req(bfqd, next, prev, blk_rq_pos(last));