From cacc7b0556739bd6018252731c0237c071ba51da Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Fri, 11 Nov 2016 20:05:35 +0800 Subject: 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 Signed-off-by: Mike Snitzer --- drivers/md/dm-io.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) (limited to 'drivers/md/dm-io.c') 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; } /* -- cgit v1.2.3