[PATCH] block: take destination bvec offsets into account in bio_copy_data_iter

[PATCH] block: take destination bvec offsets into account in bio_copy_data_iter

[Christoph Hellwig]

Appartly bcache can copy into bios that do not just contain fresh
pages but can have offsets into the bio_vecs.  Restore support for tht
in bio_copy_data_iter.

Fixes: 8b679a070c53 ("block: rewrite bio_copy_data_iter to use bvec_kmap_local and memcpy_to_bvec")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bio.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index a3893d80dccc9..8a1b3d650a7f7 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1366,10 +1366,12 @@ void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
 		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;
+		void *src_buf = bvec_kmap_local(&src_bv);
+		void *dst_buf = bvec_kmap_local(&dst_bv);
 
-		src_buf = bvec_kmap_local(&src_bv);
-		memcpy_to_bvec(&dst_bv, src_buf);
+		memcpy(dst_buf, src_buf, bytes);
+
+		kunmap_local(dst_buf);
 		kunmap_local(src_buf);
 
 		bio_advance_iter_single(src, src_iter, bytes);
-- 
2.30.2

Re: [PATCH] block: take destination bvec offsets into account in bio_copy_data_iter

[Jens Axboe]

On 5/24/22 8:39 AM, Christoph Hellwig wrote:
> Appartly bcache can copy into bios that do not just contain fresh
> pages but can have offsets into the bio_vecs.  Restore support for tht
> in bio_copy_data_iter.
> 
> Fixes: 8b679a070c53 ("block: rewrite bio_copy_data_iter to use bvec_kmap_local and memcpy_to_bvec")

Applied, but where is this sha from? The upstream one is f8b679a070c5.

-- 
Jens Axboe

Re: [PATCH] block: take destination bvec offsets into account in bio_copy_data_iter

[Christoph Hellwig]

On Fri, May 27, 2022 at 08:36:47PM -0600, Jens Axboe wrote:
> On 5/24/22 8:39 AM, Christoph Hellwig wrote:
> > Appartly bcache can copy into bios that do not just contain fresh
> > pages but can have offsets into the bio_vecs.  Restore support for tht
> > in bio_copy_data_iter.
> > 
> > Fixes: 8b679a070c53 ("block: rewrite bio_copy_data_iter to use bvec_kmap_local and memcpy_to_bvec")
> 
> Applied, but where is this sha from? The upstream one is f8b679a070c5.

Apparently from my copy and pasting discarding the initial f of that..

Re: [PATCH] block: take destination bvec offsets into account in bio_copy_data_iter

[Jens Axboe]

On 5/27/22 10:52 PM, Christoph Hellwig wrote:
> On Fri, May 27, 2022 at 08:36:47PM -0600, Jens Axboe wrote:
>> On 5/24/22 8:39 AM, Christoph Hellwig wrote:
>>> Appartly bcache can copy into bios that do not just contain fresh
>>> pages but can have offsets into the bio_vecs.  Restore support for tht
>>> in bio_copy_data_iter.
>>>
>>> Fixes: 8b679a070c53 ("block: rewrite bio_copy_data_iter to use bvec_kmap_local and memcpy_to_bvec")
>>
>> Applied, but where is this sha from? The upstream one is f8b679a070c5.
> 
> Apparently from my copy and pasting discarding the initial f of that..

Heh, my tired eyes missed that, makes sense. Anyway, I did correct it
when applying.

-- 
Jens Axboe