[PATCH V4 04/45] block: bounce: avoid direct access to bvec table

Ming Lei
2017-12-18T12:24:01Z

We will support multipage bvecs in the future, so change to iterator way
for getting bv_page of bvec from original bio.

Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/bounce.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/block/bounce.c b/block/bounce.c
index fceb1a96480b..0274c31d6c05 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -137,21 +137,20 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
static void bounce_end_io(struct bio *bio, mempool_t *pool)
{
struct bio *bio_orig = bio->bi_private;
- struct bio_vec *bvec, *org_vec;
+ struct bio_vec *bvec, orig_vec;
int i;
- int start = bio_orig->bi_iter.bi_idx;
+ struct bvec_iter orig_iter = bio_orig->bi_iter;

/*
* free up bounce indirect pages used
*/
bio_for_each_segment_all(bvec, bio, i) {
- org_vec = bio_orig->bi_io_vec + i + start;
-
- if (bvec->bv_page == org_vec->bv_page)
- continue;
-
- dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
- mempool_free(bvec->bv_page, pool);
+ orig_vec = bio_iter_iovec(bio_orig, orig_iter);
+ if (bvec->bv_page != orig_vec.bv_page) {
+ dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
+ mempool_free(bvec->bv_page, pool);
+ }
+ bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len);
}

bio_orig->bi_status = bio->bi_status;
--
2.9.5