diff options
| -rw-r--r-- | block/blk-merge.c | 65 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 69 |
2 files changed, 65 insertions, 69 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index aaec38cc37b8..ad8a226347a6 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -12,6 +12,71 @@ #include "blk.h" +/* + * Check if the two bvecs from two bios can be merged to one segment. If yes, + * no need to check gap between the two bios since the 1st bio and the 1st bvec + * in the 2nd bio can be handled in one segment. + */ +static inline bool bios_segs_mergeable(struct request_queue *q, + struct bio *prev, struct bio_vec *prev_last_bv, + struct bio_vec *next_first_bv) +{ + if (!BIOVEC_PHYS_MERGEABLE(prev_last_bv, next_first_bv)) + return false; + if (!BIOVEC_SEG_BOUNDARY(q, prev_last_bv, next_first_bv)) + return false; + if (prev->bi_seg_back_size + next_first_bv->bv_len > + queue_max_segment_size(q)) + return false; + return true; +} + +static inline bool bio_will_gap(struct request_queue *q, + struct request *prev_rq, struct bio *prev, struct bio *next) +{ + struct bio_vec pb, nb; + + if (!bio_has_data(prev) || !queue_virt_boundary(q)) + return false; + + /* + * Don't merge if the 1st bio starts with non-zero offset, otherwise it + * is quite difficult to respect the sg gap limit. We work hard to + * merge a huge number of small single bios in case of mkfs. + */ + if (prev_rq) + bio_get_first_bvec(prev_rq->bio, &pb); + else + bio_get_first_bvec(prev, &pb); + if (pb.bv_offset) + return true; + + /* + * We don't need to worry about the situation that the merged segment + * ends in unaligned virt boundary: + * + * - if 'pb' ends aligned, the merged segment ends aligned + * - if 'pb' ends unaligned, the next bio must include + * one single bvec of 'nb', otherwise the 'nb' can't + * merge with 'pb' + */ + bio_get_last_bvec(prev, &pb); + bio_get_first_bvec(next, &nb); + if (bios_segs_mergeable(q, prev, &pb, &nb)) + return false; + return __bvec_gap_to_prev(q, &pb, nb.bv_offset); +} + +static inline bool req_gap_back_merge(struct request *req, struct bio *bio) +{ + return bio_will_gap(req->q, req, req->biotail, bio); +} + +static inline bool req_gap_front_merge(struct request *req, struct bio *bio) +{ + return bio_will_gap(req->q, NULL, bio, req->bio); +} + static struct bio *blk_bio_discard_split(struct request_queue *q, struct bio *bio, struct bio_set *bs, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index bc534c857344..b7e676bb01bc 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1695,75 +1695,6 @@ static inline bool bvec_gap_to_prev(struct request_queue *q, return __bvec_gap_to_prev(q, bprv, offset); } -/* - * Check if the two bvecs from two bios can be merged to one segment. - * If yes, no need to check gap between the two bios since the 1st bio - * and the 1st bvec in the 2nd bio can be handled in one segment. - */ -static inline bool bios_segs_mergeable(struct request_queue *q, - struct bio *prev, struct bio_vec *prev_last_bv, - struct bio_vec *next_first_bv) -{ - if (!BIOVEC_PHYS_MERGEABLE(prev_last_bv, next_first_bv)) - return false; - if (!BIOVEC_SEG_BOUNDARY(q, prev_last_bv, next_first_bv)) - return false; - if (prev->bi_seg_back_size + next_first_bv->bv_len > - queue_max_segment_size(q)) - return false; - return true; -} - -static inline bool bio_will_gap(struct request_queue *q, - struct request *prev_rq, - struct bio *prev, - struct bio *next) -{ - if (bio_has_data(prev) && queue_virt_boundary(q)) { - struct bio_vec pb, nb; - - /* - * don't merge if the 1st bio starts with non-zero - * offset, otherwise it is quite difficult to respect - * sg gap limit. We work hard to merge a huge number of small - * single bios in case of mkfs. - */ - if (prev_rq) - bio_get_first_bvec(prev_rq->bio, &pb); - else - bio_get_first_bvec(prev, &pb); - if (pb.bv_offset) - return true; - - /* - * We don't need to worry about the situation that the - * merged segment ends in unaligned virt boundary: - * - * - if 'pb' ends aligned, the merged segment ends aligned - * - if 'pb' ends unaligned, the next bio must include - * one single bvec of 'nb', otherwise the 'nb' can't - * merge with 'pb' - */ - bio_get_last_bvec(prev, &pb); - bio_get_first_bvec(next, &nb); - - if (!bios_segs_mergeable(q, prev, &pb, &nb)) - return __bvec_gap_to_prev(q, &pb, nb.bv_offset); - } - - return false; -} - -static inline bool req_gap_back_merge(struct request *req, struct bio *bio) -{ - return bio_will_gap(req->q, req, req->biotail, bio); -} - -static inline bool req_gap_front_merge(struct request *req, struct bio *bio) -{ - return bio_will_gap(req->q, NULL, bio, req->bio); -} - int kblockd_schedule_work(struct work_struct *work); int kblockd_schedule_work_on(int cpu, struct work_struct *work); int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay); |