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@xxxxxxxxx>
---
drivers/md/dm-io.c | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 0bf1a12e35fe..2ef573c220fc 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 bv = bvec_iter_bvec((struct bio_vec *)dp->context_ptr,
+ dp->context_bi);
+
+ *p = bv.bv_page;
+ *len = bv.bv_len;
+ *offset = bv.bv_offset;
+
+ /* avoid to figure out it in bio_next_page() again */
+ dp->context_bi.bi_sector = (sector_t)bv.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;
}
/*
--
2.7.4
--
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