diff options
| author | Ming Lei <tom.leiming@gmail.com> | 2017-02-14 23:28:59 +0800 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2017-02-15 11:22:05 -0800 |
| commit | c18a1e09008de7d8bd82b046d38a88f4285d53f9 (patch) | |
| tree | b6db3c3286d3086c587a76da819c9272dc91b19d /block/bio.c | |
| parent | 26483819f89c5cf9d27620d70c95afeeeb9bece5 (diff) | |
| download | lwn-c18a1e09008de7d8bd82b046d38a88f4285d53f9.tar.gz lwn-c18a1e09008de7d8bd82b046d38a88f4285d53f9.zip | |
block: introduce bio_clone_bioset_partial()
md still need bio clone(not the fast version) for behind write,
and it is more efficient to use bio_clone_bioset_partial().
The idea is simple and just copy the bvecs range specified from
parameters.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'block/bio.c')
| -rw-r--r-- | block/bio.c | 61 |
1 files changed, 48 insertions, 13 deletions
diff --git a/block/bio.c b/block/bio.c index 2b375020fc49..9e2b33ddca0a 100644 --- a/block/bio.c +++ b/block/bio.c @@ -625,21 +625,20 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) } EXPORT_SYMBOL(bio_clone_fast); -/** - * bio_clone_bioset - clone a bio - * @bio_src: bio to clone - * @gfp_mask: allocation priority - * @bs: bio_set to allocate from - * - * Clone bio. Caller will own the returned bio, but not the actual data it - * points to. Reference count of returned bio will be one. - */ -struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, - struct bio_set *bs) +static struct bio *__bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, + struct bio_set *bs, int offset, + int size) { struct bvec_iter iter; struct bio_vec bv; struct bio *bio; + struct bvec_iter iter_src = bio_src->bi_iter; + + /* for supporting partial clone */ + if (offset || size != bio_src->bi_iter.bi_size) { + bio_advance_iter(bio_src, &iter_src, offset); + iter_src.bi_size = size; + } /* * Pre immutable biovecs, __bio_clone() used to just do a memcpy from @@ -663,7 +662,8 @@ struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, * __bio_clone_fast() anyways. */ - bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs); + bio = bio_alloc_bioset(gfp_mask, __bio_segments(bio_src, + &iter_src), bs); if (!bio) return NULL; bio->bi_bdev = bio_src->bi_bdev; @@ -680,7 +680,7 @@ struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0]; break; default: - bio_for_each_segment(bv, bio_src, iter) + __bio_for_each_segment(bv, bio_src, iter, iter_src) bio->bi_io_vec[bio->bi_vcnt++] = bv; break; } @@ -699,9 +699,44 @@ struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, return bio; } + +/** + * bio_clone_bioset - clone a bio + * @bio_src: bio to clone + * @gfp_mask: allocation priority + * @bs: bio_set to allocate from + * + * Clone bio. Caller will own the returned bio, but not the actual data it + * points to. Reference count of returned bio will be one. + */ +struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, + struct bio_set *bs) +{ + return __bio_clone_bioset(bio_src, gfp_mask, bs, 0, + bio_src->bi_iter.bi_size); +} EXPORT_SYMBOL(bio_clone_bioset); /** + * bio_clone_bioset_partial - clone a partial bio + * @bio_src: bio to clone + * @gfp_mask: allocation priority + * @bs: bio_set to allocate from + * @offset: cloned starting from the offset + * @size: size for the cloned bio + * + * Clone bio. Caller will own the returned bio, but not the actual data it + * points to. Reference count of returned bio will be one. + */ +struct bio *bio_clone_bioset_partial(struct bio *bio_src, gfp_t gfp_mask, + struct bio_set *bs, int offset, + int size) +{ + return __bio_clone_bioset(bio_src, gfp_mask, bs, offset, size); +} +EXPORT_SYMBOL(bio_clone_bioset_partial); + +/** * bio_add_pc_page - attempt to add page to bio * @q: the target queue * @bio: destination bio |