block: rewrite bio_copy_data_iter to use bvec_kmap_local and memcpy_to_bvec

Use the proper helpers instead of open coding the copy.

Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/block/bio.c b/block/bio.c
index 1d7abdb83a39156efc09f27eeef287480f45d6d4..c14d2e66c084c5c22b5ae8ddb10384c58ef93f4e 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1186,27 +1186,15 @@ EXPORT_SYMBOL(bio_advance);
 void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
                        struct bio *src, struct bvec_iter *src_iter)
 {
-       struct bio_vec src_bv, dst_bv;
-       void *src_p, *dst_p;
-       unsigned bytes;
-
        while (src_iter->bi_size && dst_iter->bi_size) {
-               src_bv = bio_iter_iovec(src, *src_iter);
-               dst_bv = bio_iter_iovec(dst, *dst_iter);
-
-               bytes = min(src_bv.bv_len, dst_bv.bv_len);
-
-               src_p = kmap_atomic(src_bv.bv_page);
-               dst_p = kmap_atomic(dst_bv.bv_page);
-
-               memcpy(dst_p + dst_bv.bv_offset,
-                      src_p + src_bv.bv_offset,
-                      bytes);
-
-               kunmap_atomic(dst_p);
-               kunmap_atomic(src_p);
-
-               flush_dcache_page(dst_bv.bv_page);
+               struct bio_vec src_bv = bio_iter_iovec(src, *src_iter);
+               struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter);
+               unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);
+               void *src_buf;
+
+               src_buf = bvec_kmap_local(&src_bv);
+               memcpy_to_bvec(&dst_bv, src_buf);
+               kunmap_local(src_buf);
 
                bio_advance_iter_single(src, src_iter, bytes);
                bio_advance_iter_single(dst, dst_iter, bytes);