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| author | Ming Lei <tom.leiming@gmail.com> | 2016-11-11 20:05:35 +0800 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2016-11-21 09:51:57 -0500 |
| commit | cacc7b0556739bd6018252731c0237c071ba51da (patch) | |
| tree | 8c5cb13d6cb60a9f79616f3887318b9743202c56 /drivers/md/dm-io.c | |
| parent | 4f9c74c6043891d415730bcb153c579be35c352f (diff) | |
| download | linux-cacc7b0556739bd6018252731c0237c071ba51da.tar.bz2 | |
dm io: use bvec iterator helpers to implement .get_page and .next_page
Firstly we have mature bvec/bio iterator helper for iterate each
page in one bio, not necessary to reinvent a wheel to do that.
Secondly the coming multipage bvecs requires this patch.
Also add comments about the direct access to bvec table.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-io.c')
| -rw-r--r-- | drivers/md/dm-io.c | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c index 0bf1a12e35fe..03940bf36f6c 100644 --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -162,7 +162,10 @@ struct dpages { struct page **p, unsigned long *len, unsigned *offset); void (*next_page)(struct dpages *dp); - unsigned context_u; + union { + unsigned context_u; + struct bvec_iter context_bi; + }; void *context_ptr; void *vma_invalidate_address; @@ -204,25 +207,36 @@ static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offse static void bio_get_page(struct dpages *dp, struct page **p, unsigned long *len, unsigned *offset) { - struct bio_vec *bvec = dp->context_ptr; - *p = bvec->bv_page; - *len = bvec->bv_len - dp->context_u; - *offset = bvec->bv_offset + dp->context_u; + struct bio_vec bvec = bvec_iter_bvec((struct bio_vec *)dp->context_ptr, + dp->context_bi); + + *p = bvec.bv_page; + *len = bvec.bv_len; + *offset = bvec.bv_offset; + + /* avoid figuring it out again in bio_next_page() */ + dp->context_bi.bi_sector = (sector_t)bvec.bv_len; } static void bio_next_page(struct dpages *dp) { - struct bio_vec *bvec = dp->context_ptr; - dp->context_ptr = bvec + 1; - dp->context_u = 0; + unsigned int len = (unsigned int)dp->context_bi.bi_sector; + + bvec_iter_advance((struct bio_vec *)dp->context_ptr, + &dp->context_bi, len); } static void bio_dp_init(struct dpages *dp, struct bio *bio) { dp->get_page = bio_get_page; dp->next_page = bio_next_page; - dp->context_ptr = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); - dp->context_u = bio->bi_iter.bi_bvec_done; + + /* + * We just use bvec iterator to retrieve pages, so it is ok to + * access the bvec table directly here + */ + dp->context_ptr = bio->bi_io_vec; + dp->context_bi = bio->bi_iter; } /* |