On Thu, Feb 27, 2025 at 06:15:09PM +0800, Herbert Xu wrote:
> Use the acomp virtual address interface.
>
> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
I can't speak to the rest of the series, but I like what this patch is
doing in zswap. Together with the recent zsmalloc changes, we should be
able to drop the alternative memcpy path completely, without needing to
use kmap_to_page() or removing the warning the highmem code.
Thanks for doing this!
> ---
> mm/zswap.c | 23 ++++++++---------------
> 1 file changed, 8 insertions(+), 15 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 6504174fbc6a..2b5a2398a9be 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -925,27 +925,20 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry,
> struct zswap_pool *pool)
> {
> struct crypto_acomp_ctx *acomp_ctx;
> - struct scatterlist input, output;
> int comp_ret = 0, alloc_ret = 0;
> unsigned int dlen = PAGE_SIZE;
> unsigned long handle;
> struct zpool *zpool;
> + const u8 *src;
> char *buf;
> gfp_t gfp;
> u8 *dst;
>
> acomp_ctx = acomp_ctx_get_cpu_lock(pool);
> + src = kmap_local_page(page);
> dst = acomp_ctx->buffer;
> - sg_init_table(&input, 1);
> - sg_set_page(&input, page, PAGE_SIZE, 0);
>
> - /*
> - * We need PAGE_SIZE * 2 here since there maybe over-compression case,
> - * and hardware-accelerators may won't check the dst buffer size, so
> - * giving the dst buffer with enough length to avoid buffer overflow.
> - */
> - sg_init_one(&output, dst, PAGE_SIZE * 2);
> - acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen);
> + acomp_request_set_virt(acomp_ctx->req, src, dst, PAGE_SIZE, dlen);
>
> /*
> * it maybe looks a little bit silly that we send an asynchronous request,
> @@ -960,6 +953,7 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry,
> * acomp instance, so multiple threads can do (de)compression in parallel.
> */
> comp_ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
> + kunmap_local(src);
> dlen = acomp_ctx->req->dlen;
> if (comp_ret)
> goto unlock;
> @@ -994,9 +988,9 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry,
> static void zswap_decompress(struct zswap_entry *entry, struct folio *folio)
> {
> struct zpool *zpool = entry->pool->zpool;
> - struct scatterlist input, output;
> struct crypto_acomp_ctx *acomp_ctx;
> u8 *src;
> + u8 *dst;
>
> acomp_ctx = acomp_ctx_get_cpu_lock(entry->pool);
> src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO);
> @@ -1016,11 +1010,10 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio)
> zpool_unmap_handle(zpool, entry->handle);
> }
>
> - sg_init_one(&input, src, entry->length);
> - sg_init_table(&output, 1);
> - sg_set_folio(&output, folio, PAGE_SIZE, 0);
> - acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, PAGE_SIZE);
> + dst = kmap_local_folio(folio, 0);
> + acomp_request_set_virt(acomp_ctx->req, src, dst, entry->length, PAGE_SIZE);
> BUG_ON(crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait));
> + kunmap_local(dst);
> BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE);
>
> if (src != acomp_ctx->buffer)
> --
> 2.39.5
>
