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>
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@ -11,13 +11,16 @@
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static struct bio *blk_bio_discard_split(struct request_queue *q,
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struct bio *bio,
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struct bio_set *bs)
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struct bio_set *bs,
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unsigned *nsegs)
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{
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unsigned int max_discard_sectors, granularity;
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int alignment;
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sector_t tmp;
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unsigned split_sectors;
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*nsegs = 1;
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/* Zero-sector (unknown) and one-sector granularities are the same. */
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granularity = max(q->limits.discard_granularity >> 9, 1U);
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@ -51,8 +54,11 @@ static struct bio *blk_bio_discard_split(struct request_queue *q,
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static struct bio *blk_bio_write_same_split(struct request_queue *q,
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struct bio *bio,
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struct bio_set *bs)
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struct bio_set *bs,
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unsigned *nsegs)
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{
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*nsegs = 1;
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if (!q->limits.max_write_same_sectors)
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return NULL;
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@ -64,7 +70,8 @@ static struct bio *blk_bio_write_same_split(struct request_queue *q,
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static struct bio *blk_bio_segment_split(struct request_queue *q,
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struct bio *bio,
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struct bio_set *bs)
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struct bio_set *bs,
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unsigned *segs)
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{
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struct bio_vec bv, bvprv, *bvprvp = NULL;
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struct bvec_iter iter;
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@ -106,22 +113,30 @@ new_segment:
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sectors += bv.bv_len >> 9;
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}
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*segs = nsegs;
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return NULL;
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split:
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*segs = nsegs;
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return bio_split(bio, sectors, GFP_NOIO, bs);
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}
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void blk_queue_split(struct request_queue *q, struct bio **bio,
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struct bio_set *bs)
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{
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struct bio *split;
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struct bio *split, *res;
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unsigned nsegs;
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if ((*bio)->bi_rw & REQ_DISCARD)
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split = blk_bio_discard_split(q, *bio, bs);
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split = blk_bio_discard_split(q, *bio, bs, &nsegs);
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else if ((*bio)->bi_rw & REQ_WRITE_SAME)
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split = blk_bio_write_same_split(q, *bio, bs);
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split = blk_bio_write_same_split(q, *bio, bs, &nsegs);
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else
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split = blk_bio_segment_split(q, *bio, q->bio_split);
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split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs);
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/* physical segments can be figured out during splitting */
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res = split ? split : *bio;
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res->bi_phys_segments = nsegs;
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bio_set_flag(res, BIO_SEG_VALID);
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if (split) {
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bio_chain(split, *bio);
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