extern struct kmem_cache *blk_requestq_cachep;
extern struct kobj_type blk_queue_ktype;
-void rq_init(struct request_queue *q, struct request *rq);
void init_request_from_bio(struct request *req, struct bio *bio);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);