[PATCH] btrfs: zlib: use memcpy_from_folio() in copy_data_into_buffer()

[PATCH] btrfs: zlib: use memcpy_from_folio() in copy_data_into_buffer()

[fdmanana]

From: Filipe Manana <fdmanana@suse.com>

We are manually mapping the folio, copying from it with memcpy() and then
unmapping, but this can all simply be done with memcpy_from_folio() that
is provided by the MM layer. So use memcpy_from_folio() instead.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/zlib.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index e995d0b1452b..1f2a91f966a2 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -122,7 +122,6 @@ static int copy_data_into_buffer(struct address_space *mapping,
 
 	while (cur < filepos + length) {
 		struct folio *folio;
-		void *data_in;
 		unsigned int offset;
 		unsigned long copy_length;
 		int ret;
@@ -135,9 +134,8 @@ static int copy_data_into_buffer(struct address_space *mapping,
 		copy_length = min(folio_size(folio) - offset,
 				  filepos + length - cur);
 
-		data_in = kmap_local_folio(folio, offset);
-		memcpy(workspace->buf + cur - filepos, data_in, copy_length);
-		kunmap_local(data_in);
+		memcpy_from_folio(workspace->buf + cur - filepos, folio, offset,
+				  copy_length);
 		folio_put(folio);
 		cur += copy_length;
 	}
-- 
2.53.0

Re: [PATCH] btrfs: zlib: use memcpy_from_folio() in copy_data_into_buffer()

[Qu Wenruo]

在 2026/10/27 04:09, fdmanana@kernel.org 写道:
> From: Filipe Manana <fdmanana@suse.com>
> 
> We are manually mapping the folio, copying from it with memcpy() and then
> unmapping, but this can all simply be done with memcpy_from_folio() that
> is provided by the MM layer. So use memcpy_from_folio() instead.
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu

> ---
>   fs/btrfs/zlib.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
> index e995d0b1452b..1f2a91f966a2 100644
> --- a/fs/btrfs/zlib.c
> +++ b/fs/btrfs/zlib.c
> @@ -122,7 +122,6 @@ static int copy_data_into_buffer(struct address_space *mapping,
>   
>   	while (cur < filepos + length) {
>   		struct folio *folio;
> -		void *data_in;
>   		unsigned int offset;
>   		unsigned long copy_length;
>   		int ret;
> @@ -135,9 +134,8 @@ static int copy_data_into_buffer(struct address_space *mapping,
>   		copy_length = min(folio_size(folio) - offset,
>   				  filepos + length - cur);
>   
> -		data_in = kmap_local_folio(folio, offset);
> -		memcpy(workspace->buf + cur - filepos, data_in, copy_length);
> -		kunmap_local(data_in);
> +		memcpy_from_folio(workspace->buf + cur - filepos, folio, offset,
> +				  copy_length);
>   		folio_put(folio);
>   		cur += copy_length;
>   	}

Re: [PATCH] btrfs: zlib: use memcpy_from_folio() in copy_data_into_buffer()

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>