On Thu, Feb 22, 2024 at 03:06:17PM +1300, Barry Song wrote:
>
> - scatterwalk_map_and_copy(scratch->src, req->src, 0, req->slen, 0);
> + if (sg_nents(req->src) == 1 && !PageHighMem(sg_page(req->src))) {
> + src = page_to_virt(sg_page(req->src)) + req->src->offset;
Incidentally this made me look at other uses of PageHighMem in
the kernel.
The one in copy_page_from_iter_atomic looks buggy because it assumes
that the kmap never maps a page if PageHighMem is false, which is not
the case for CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP.
> @@ -152,8 +165,12 @@ static int scomp_acomp_comp_decomp(struct acomp_req *req, int dir)
> ret = -ENOSPC;
> goto out;
> }
> - scatterwalk_map_and_copy(scratch->dst, req->dst, 0, req->dlen,
> - 1);
> + if (dst == scratch->dst) {
> + scatterwalk_map_and_copy(scratch->dst, req->dst, 0,
> + req->dlen, 1);
> + } else {
> + flush_dcache_page(sg_page(req->dst));
I think this is still wrong for the > PAGE_SIZE case. The existing
code flushes each page sequentially but the new code only flushes the
first page.
Thanks,
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
