linux-master/block/elevator.c

54 #define rq_hash_key(rq)		(blk_rq_pos(rq) + blk_rq_sectors(rq))
58  * merged with rq.
60 static bool elv_iosched_allow_bio_merge(struct request *rq, struct bio *bio)
62 	struct request_queue *q = rq->q;
66 		return e->type->ops.allow_merge(q, rq, bio);
74 bool elv_bio_merge_ok(struct request *rq, struct bio *bio)
76 	if (!blk_rq_merge_ok(rq, bio))
79 	if (!elv_iosched_allow_bio_merge(rq, bio))
166 static inline void __elv_rqhash_del(struct request *rq)
168 	hash_del(&rq->hash);
169 	rq->rq_flags &= ~RQF_HASHED;
172 void elv_rqhash_del(struct request_queue *q, struct request *rq)
174 	if (ELV_ON_HASH(rq))
175 		__elv_rqhash_del(rq);
179 void elv_rqhash_add(struct request_queue *q, struct request *rq)
183 	BUG_ON(ELV_ON_HASH(rq));
184 	hash_add(e->hash, &rq->hash, rq_hash_key(rq));
185 	rq->rq_flags |= RQF_HASHED;
189 void elv_rqhash_reposition(struct request_queue *q, struct request *rq)
191 	__elv_rqhash_del(rq);
192 	elv_rqhash_add(q, rq);
199 	struct request *rq;
201 	hash_for_each_possible_safe(e->hash, rq, next, hash, offset) {
202 		BUG_ON(!ELV_ON_HASH(rq));
204 		if (unlikely(!rq_mergeable(rq))) {
205 			__elv_rqhash_del(rq);
209 		if (rq_hash_key(rq) == offset)
210 			return rq;
220 void elv_rb_add(struct rb_root *root, struct request *rq)
230 		if (blk_rq_pos(rq) < blk_rq_pos(__rq))
232 		else if (blk_rq_pos(rq) >= blk_rq_pos(__rq))
236 	rb_link_node(&rq->rb_node, parent, p);
237 	rb_insert_color(&rq->rb_node, root);
241 void elv_rb_del(struct rb_root *root, struct request *rq)
243 	BUG_ON(RB_EMPTY_NODE(&rq->rb_node));
244 	rb_erase(&rq->rb_node, root);
245 	RB_CLEAR_NODE(&rq->rb_node);
252 	struct request *rq;
255 		rq = rb_entry(n, struct request, rb_node);
257 		if (sector < blk_rq_pos(rq))
259 		else if (sector > blk_rq_pos(rq))
262 			return rq;
319  * we can append 'rq' to an existing request, so we can throw 'rq' away
325 bool elv_attempt_insert_merge(struct request_queue *q, struct request *rq,
337 	if (q->last_merge && blk_attempt_req_merge(q, q->last_merge, rq)) {
338 		list_add(&rq->queuelist, free);
350 		__rq = elv_rqhash_find(q, blk_rq_pos(rq));
351 		if (!__rq || !blk_attempt_req_merge(q, __rq, rq))
354 		list_add(&rq->queuelist, free);
357 		rq = __rq;
363 void elv_merged_request(struct request_queue *q, struct request *rq,
369 		e->type->ops.request_merged(q, rq, type);
372 		elv_rqhash_reposition(q, rq);
374 	q->last_merge = rq;
377 void elv_merge_requests(struct request_queue *q, struct request *rq,
383 		e->type->ops.requests_merged(q, rq, next);
385 	elv_rqhash_reposition(q, rq);
386 	q->last_merge = rq;
389 struct request *elv_latter_request(struct request_queue *q, struct request *rq)
394 		return e->type->ops.next_request(q, rq);
399 struct request *elv_former_request(struct request_queue *q, struct request *rq)
404 		return e->type->ops.former_request(q, rq);
758 				      struct request *rq)
760 	struct rb_node *rbprev = rb_prev(&rq->rb_node);
770 				      struct request *rq)
772 	struct rb_node *rbnext = rb_next(&rq->rb_node);