 prev = rq->queuelist.prev; if (prev != &q->queue_head && prev != &rq->queuelist) return list_entry_rq(prev);  
struct request *elv_former_request(request_queue_t *q, struct request *rq){	struct list_head *prev;	elevator_t *e = q->elevator;	if (e->ops->elevator_former_req_fn)		return e->ops->elevator_former_req_fn(q, rq);	prev = rq->queuelist.prev;	if (prev != &q->queue_head && prev != &rq->queuelist)		return list_entry_rq(prev);	return NULL;}
4520	/local/tlutelli/issta_data/temp/c/2005_temp/2005/4520/3beb2077125d8457118140653e75efc998ac6630/elevator.c/buggy/block/elevator.c