linux-master/block/blk-merge.c

18 #include "blk-rq-qos.h"
409 unsigned int blk_recalc_rq_segments(struct request *rq)
416 	if (!rq->bio)
419 	switch (bio_op(rq->bio)) {
422 		if (queue_max_discard_segments(rq->q) > 1) {
423 			struct bio *bio = rq->bio;
436 	rq_for_each_bvec(bv, rq, iter)
437 		bvec_split_segs(&rq->q->limits, &bv, &nr_phys_segs, &bytes,
562  * must make sure sg can hold rq->nr_phys_segments entries
564 int __blk_rq_map_sg(struct request_queue *q, struct request *rq,
569 	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
570 		nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, last_sg);
571 	else if (rq->bio)
572 		nsegs = __blk_bios_map_sg(q, rq->bio, sglist, last_sg);
581 	WARN_ON(nsegs > blk_rq_nr_phys_segments(rq));
587 static inline unsigned int blk_rq_get_max_sectors(struct request *rq,
590 	struct request_queue *q = rq->q;
593 	if (blk_rq_is_passthrough(rq))
596 	max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
598 	    req_op(rq) == REQ_OP_DISCARD ||
599 	    req_op(rq) == REQ_OP_SECURE_ERASE)
723  * @rq: request to mark as mixed merge
726  *     @rq is about to be mixed merged.  Make sure the attributes
727  *     which can be mixed are set in each bio and mark @rq as mixed
730 static void blk_rq_set_mixed_merge(struct request *rq)
732 	blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
735 	if (rq->rq_flags & RQF_MIXED_MERGE)
739 	 * @rq will no longer represent mixable attributes for all the
743 	for (bio = rq->bio; bio; bio = bio->bi_next) {
748 	rq->rq_flags |= RQF_MIXED_MERGE;
825 	 * from next to rq and release next. merge_requests_fn
891 		struct request *rq)
893 	struct request *next = elv_latter_request(q, rq);
896 		return attempt_merge(q, rq, next);
902 		struct request *rq)
904 	struct request *prev = elv_former_request(q, rq);
907 		return attempt_merge(q, prev, rq);
913  * Try to merge 'next' into 'rq'. Return true if the merge happened, false
917 bool blk_attempt_req_merge(struct request_queue *q, struct request *rq,
920 	return attempt_merge(q, rq, next);
923 bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
925 	if (!rq_mergeable(rq) || !bio_mergeable(bio))
928 	if (req_op(rq) != bio_op(bio))
932 	if (bio_data_dir(bio) != rq_data_dir(rq))
936 	if (!blk_cgroup_mergeable(rq, bio))
939 	/* only merge integrity protected bio into ditto rq */
940 	if (blk_integrity_merge_bio(rq->q, rq, bio) == false)
944 	if (!bio_crypt_rq_ctx_compatible(rq, bio))
948 	if (rq->write_hint != bio->bi_write_hint)
951 	if (rq->ioprio != bio_prio(bio))
957 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio)
959 	if (blk_discard_mergable(rq))
961 	else if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector)
963 	else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector)
1069 						   struct request *rq,
1074 	if (!blk_rq_merge_ok(rq, bio))
1077 	switch (blk_try_merge(rq, bio)) {
1079 		if (!sched_allow_merge || blk_mq_sched_allow_merge(q, rq, bio))
1080 			return bio_attempt_back_merge(rq, bio, nr_segs);
1083 		if (!sched_allow_merge || blk_mq_sched_allow_merge(q, rq, bio))
1084 			return bio_attempt_front_merge(rq, bio, nr_segs);
1087 		return bio_attempt_discard_merge(q, rq, bio);
1119 	struct request *rq;
1124 	rq_list_for_each(&plug->mq_list, rq) {
1125 		if (rq->q == q) {
1126 			if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) ==
1149 	struct request *rq;
1152 	list_for_each_entry_reverse(rq, list, queuelist) {
1156 		switch (blk_attempt_bio_merge(q, rq, bio, nr_segs, true)) {
1174 	struct request *rq;
1176 	switch (elv_merge(q, &rq, bio)) {
1178 		if (!blk_mq_sched_allow_merge(q, rq, bio))
1180 		if (bio_attempt_back_merge(rq, bio, nr_segs) != BIO_MERGE_OK)
1182 		*merged_request = attempt_back_merge(q, rq);
1184 			elv_merged_request(q, rq, ELEVATOR_BACK_MERGE);
1187 		if (!blk_mq_sched_allow_merge(q, rq, bio))
1189 		if (bio_attempt_front_merge(rq, bio, nr_segs) != BIO_MERGE_OK)
1191 		*merged_request = attempt_front_merge(q, rq);
1193 			elv_merged_request(q, rq, ELEVATOR_FRONT_MERGE);
1196 		return bio_attempt_discard_merge(q, rq, bio) == BIO_MERGE_OK;