2024-03-17 23:14:00

by Guenter Roeck

Subject: Re: [PATCH v7] crypto: scompress: remove memcpy if sg_nents is 1 and pages are lowmem

Hi,

On Sat, Mar 02, 2024 at 08:27:45AM +1300, Barry Song wrote:
[ ... ]
> @@ -152,8 +165,17 @@ 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 {
> + int nr_pages = DIV_ROUND_UP(req->dst->offset + req->dlen, PAGE_SIZE);
> + int i;
> + struct page *dst_page = sg_page(req->dst);
> +
> + for (i = 0; i < nr_pages; i++)
> + flush_dcache_page(dst_page + i);

flush_dcache_page() is an empty macro on some architectures
such as xtensa. This results in

Building xtensa:allmodconfig ... failed
--------------
Error log:
crypto/scompress.c: In function 'scomp_acomp_comp_decomp':
crypto/scompress.c:174:38: error: unused variable 'dst_page'

on the affected architectures.

Guenter

2024-03-17 23:48:44

by Barry Song

Subject: Re: [PATCH v7] crypto: scompress: remove memcpy if sg_nents is 1 and pages are lowmem

On Mon, Mar 18, 2024 at 7:13 AM Guenter Roeck <[email protected]> wrote:
>
> Hi,
>
> On Sat, Mar 02, 2024 at 08:27:45AM +1300, Barry Song wrote:
> [ ... ]
> > @@ -152,8 +165,17 @@ 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 {
> > + int nr_pages = DIV_ROUND_UP(req->dst->offset + req->dlen, PAGE_SIZE);
> > + int i;
> > + struct page *dst_page = sg_page(req->dst);
> > +
> > + for (i = 0; i < nr_pages; i++)
> > + flush_dcache_page(dst_page + i);
>
> flush_dcache_page() is an empty macro on some architectures
> such as xtensa. This results in

Hi Guenter,

this is a bug of xtensa, could you test the patch:
https://lore.kernel.org/all/[email protected]/


>
> Building xtensa:allmodconfig ... failed
> --------------
> Error log:
> crypto/scompress.c: In function 'scomp_acomp_comp_decomp':
> crypto/scompress.c:174:38: error: unused variable 'dst_page'
>
> on the affected architectures.
>
> Guenter

Thanks
Barry