Revert "block: rewrite bio_copy_data_iter to use bvec_kmap_local and memcpy_to_bvec"

This reverts commit f8b679a070c536600c64a78c83b96aa617f8fa71.

1 files changed, 20 insertions, 8 deletions

diff --git a/block/bio.c b/block/bio.c
index 681142a6b01a..3c9cc0000168 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1284,15 +1284,27 @@ 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) {
-		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);
+		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);
 
 		bio_advance_iter_single(src, src_iter, bytes);
 		bio_advance_iter_single(dst, dst_iter, bytes);