[PATCH 08/26] block: Convert bio_copy_data() to bvec_iter

Kent Overstreet
2013-06-09T02:25:53Z

Our fancy new bvec iterator makes code like this much easier to write.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
---
fs/bio.c | 60 +++++++++++++++++++++++++-----------------------------------
1 file changed, 25 insertions(+), 35 deletions(-)

diff --git a/fs/bio.c b/fs/bio.c
index 92a92bc..d4200f4 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -852,58 +852,48 @@ EXPORT_SYMBOL(bio_alloc_pages);
*/
void bio_copy_data(struct bio *dst, struct bio *src)
{
- struct bio_vec *src_bv, *dst_bv;
- unsigned src_offset, dst_offset, bytes;
+ struct bvec_iter src_iter, dst_iter;
+ struct bio_vec src_bv, dst_bv;
void *src_p, *dst_p;
+ unsigned bytes;

- src_bv = __bio_iovec(src);
- dst_bv = __bio_iovec(dst);
-
- src_offset = src_bv->bv_offset;
- dst_offset = dst_bv->bv_offset;
+ src_iter = src->bi_iter;
+ dst_iter = dst->bi_iter;

while (1) {
- if (src_offset == src_bv->bv_offset + src_bv->bv_len) {
- src_bv++;
- if (src_bv == bio_iovec_idx(src, src->bi_vcnt)) {
- src = src->bi_next;
- if (!src)
- break;
-
- src_bv = __bio_iovec(src);
- }
+ if (!src_iter.bi_size) {
+ src = src->bi_next;
+ if (!src)
+ break;

- src_offset = src_bv->bv_offset;
+ src_iter = src->bi_iter;
}

- if (dst_offset == dst_bv->bv_offset + dst_bv->bv_len) {
- dst_bv++;
- if (dst_bv == bio_iovec_idx(dst, dst->bi_vcnt)) {
- dst = dst->bi_next;
- if (!dst)
- break;
-
- dst_bv = __bio_iovec(dst);
- }
+ if (!dst_iter.bi_size) {
+ dst = dst->bi_next;
+ if (!dst)
+ break;

- dst_offset = dst_bv->bv_offset;
+ dst_iter = dst->bi_iter;
}

- bytes = min(dst_bv->bv_offset + dst_bv->bv_len - dst_offset,
- src_bv->bv_offset + src_bv->bv_len - src_offset);
+ src_bv = bio_iovec_iter(src, src_iter);
+ dst_bv = bio_iovec_iter(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);
+ 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,
+ memcpy(dst_p + dst_bv.bv_offset,
+ src_p + src_bv.bv_offset,
bytes);

kunmap_atomic(dst_p);
kunmap_atomic(src_p);

- src_offset += bytes;
- dst_offset += bytes;
+ bio_advance_iter(src, &src_iter, bytes);
+ bio_advance_iter(dst, &dst_iter, bytes);
}
}
EXPORT_SYMBOL(bio_copy_data);
--
1.8.3.rc1