Re: [PATCH v3 11/12] mm/gup_benchmark: support pin_user_pages() and related calls

Kirill A. Shutemov
2020-02-03T21:55:44Z

On Mon, Feb 03, 2020 at 01:17:40PM -0800, John Hubbard wrote:
> On 2/3/20 5:58 AM, Kirill A. Shutemov wrote:
> ...
> >> @@ -19,6 +21,48 @@ struct gup_benchmark {
> >> __u64 expansion[10]; /* For future use */
> >> };
> >>
> >> +static void put_back_pages(unsigned int cmd, struct page **pages,
> >> + unsigned long nr_pages)
> >> +{
> >> + int i;
> >> +
> >> + switch (cmd) {
> >> + case GUP_FAST_BENCHMARK:
> >> + case GUP_LONGTERM_BENCHMARK:
> >> + case GUP_BENCHMARK:
> >> + for (i = 0; i < nr_pages; i++)
> >
> > 'i' is 'int' and 'nr_pages' is 'unsigned long'.
> > There's space for trouble :P
> >
>
> Yes, I've changed it to "unsigned int", thanks.

I'm confused. If nr_pages is more than UINT_MAX, this is endless loop.
Hm?

--
Kirill A. Shutemov