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| author | Ming Lei <ming.lei@canonical.com> | 2015-10-20 23:13:52 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-10-21 15:00:50 -0600 |
| commit | bdced438acd83ad83a6c6fc7f50099b820245ddb (patch) | |
| tree | 441b9c9b16d55c157db90c499ba4fd2821bfe60b | |
| parent | 0809e3ac62319dc7534b64f95ac37e230d740e8a (diff) | |
| download | linux-bdced438acd83ad83a6c6fc7f50099b820245ddb.tar.gz linux-bdced438acd83ad83a6c6fc7f50099b820245ddb.tar.bz2 linux-bdced438acd83ad83a6c6fc7f50099b820245ddb.zip | |
block: setup bi_phys_segments after splitting
The number of bio->bi_phys_segments is always obtained
during bio splitting, so it is natural to setup it
just after bio splitting, then we can avoid to compute
nr_segment again during merge.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | block/blk-merge.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index c4e9c37f3e38..22293fdf6514 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -11,13 +11,16 @@ static struct bio *blk_bio_discard_split(struct request_queue *q, struct bio *bio, - struct bio_set *bs) + struct bio_set *bs, + unsigned *nsegs) { unsigned int max_discard_sectors, granularity; int alignment; sector_t tmp; unsigned split_sectors; + *nsegs = 1; + /* Zero-sector (unknown) and one-sector granularities are the same. */ granularity = max(q->limits.discard_granularity >> 9, 1U); @@ -51,8 +54,11 @@ static struct bio *blk_bio_discard_split(struct request_queue *q, static struct bio *blk_bio_write_same_split(struct request_queue *q, struct bio *bio, - struct bio_set *bs) + struct bio_set *bs, + unsigned *nsegs) { + *nsegs = 1; + if (!q->limits.max_write_same_sectors) return NULL; @@ -64,7 +70,8 @@ static struct bio *blk_bio_write_same_split(struct request_queue *q, static struct bio *blk_bio_segment_split(struct request_queue *q, struct bio *bio, - struct bio_set *bs) + struct bio_set *bs, + unsigned *segs) { struct bio_vec bv, bvprv, *bvprvp = NULL; struct bvec_iter iter; @@ -106,22 +113,30 @@ new_segment: sectors += bv.bv_len >> 9; } + *segs = nsegs; return NULL; split: + *segs = nsegs; return bio_split(bio, sectors, GFP_NOIO, bs); } void blk_queue_split(struct request_queue *q, struct bio **bio, struct bio_set *bs) { - struct bio *split; + struct bio *split, *res; + unsigned nsegs; if ((*bio)->bi_rw & REQ_DISCARD) - split = blk_bio_discard_split(q, *bio, bs); + split = blk_bio_discard_split(q, *bio, bs, &nsegs); else if ((*bio)->bi_rw & REQ_WRITE_SAME) - split = blk_bio_write_same_split(q, *bio, bs); + split = blk_bio_write_same_split(q, *bio, bs, &nsegs); else - split = blk_bio_segment_split(q, *bio, q->bio_split); + split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs); + + /* physical segments can be figured out during splitting */ + res = split ? split : *bio; + res->bi_phys_segments = nsegs; + bio_set_flag(res, BIO_SEG_VALID); if (split) { bio_chain(split, *bio); |