On Wed, 28 Jun 2023 00:12:40 +0800
Gao Xiang <[email protected]> wrote:

> Use memcpy_to_page() instead of open-coding them.
> 
> In addition, add a missing flush_dcache_page() even though almost all
> modern architectures clear `PG_dcache_clean` flag for new file cache
> pages so that it doesn't change anything in practice.
> 
> Signed-off-by: Gao Xiang <[email protected]>

Reviewed-by: Yue Hu <[email protected]>

> ---
> preliminary tested with silesia dataset.
> 
>  fs/erofs/decompressor.c | 19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> index ad53cf52d899..cfad1eac7fd9 100644
> --- a/fs/erofs/decompressor.c
> +++ b/fs/erofs/decompressor.c
> @@ -328,7 +328,7 @@ static int z_erofs_transform_plain(struct 
> z_erofs_decompress_req *rq,
>       const unsigned int lefthalf = rq->outputsize - righthalf;
>       const unsigned int interlaced_offset =
>               rq->alg == Z_EROFS_COMPRESSION_SHIFTED ? 0 : rq->pageofs_out;
> -     unsigned char *src, *dst;
> +     u8 *src;
>  
>       if (outpages > 2 && rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
>               DBG_BUGON(1);
> @@ -341,22 +341,19 @@ static int z_erofs_transform_plain(struct 
> z_erofs_decompress_req *rq,
>       }
>  
>       src = kmap_local_page(rq->in[inpages - 1]) + rq->pageofs_in;
> -     if (rq->out[0]) {
> -             dst = kmap_local_page(rq->out[0]);
> -             memcpy(dst + rq->pageofs_out, src + interlaced_offset,
> -                    righthalf);
> -             kunmap_local(dst);
> -     }
> +     if (rq->out[0])
> +             memcpy_to_page(rq->out[0], rq->pageofs_out,
> +                            src + interlaced_offset, righthalf);
>  
>       if (outpages > inpages) {
>               DBG_BUGON(!rq->out[outpages - 1]);
>               if (rq->out[outpages - 1] != rq->in[inpages - 1]) {
> -                     dst = kmap_local_page(rq->out[outpages - 1]);
> -                     memcpy(dst, interlaced_offset ? src :
> -                                     (src + righthalf), lefthalf);
> -                     kunmap_local(dst);
> +                     memcpy_to_page(rq->out[outpages - 1], 0, src +
> +                                     (interlaced_offset ? 0 : righthalf),
> +                                    lefthalf);
>               } else if (!interlaced_offset) {
>                       memmove(src, src + righthalf, lefthalf);
> +                     flush_dcache_page(rq->in[inpages - 1]);
>               }
>       }
>       kunmap_local(src);

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