block: bounce: avoid direct access to bvec table

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>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files 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;