[PATCH v3 14/49] block: bounce: avoid direct access to bvec table

[Ming Lei]

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

diff --git a/block/bounce.c b/block/bounce.c
index 5793c2dc1a15..e57cf2bdcd27 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -136,21 +136,20 @@ 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;
-- 
2.9.4