Re: [PATCH v2 1/3] mm/gup_benchmark: handle gup failures

On Sat, Apr 07, 2018 at 01:08:43PM -0700, Linus Torvalds wrote:

On Thu, Apr 5, 2018 at 2:03 PM, Michael S. Tsirkin mst@redhat.com wrote:

...

            nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i);

•           i += nr;
  

•           if (nr > 0)
  

•                   i += nr;
  

Can we just make this robust while at it, and just make it

    if (nr <= 0)
            break;

instead? Then it doesn't care about zero vs negative error, and wouldn't get stuck in an endless loop if it got zero.

         Linus

I don't mind though it alredy breaks out on the next cycle:

if (nr != gup->nr_pages_per_call) break;

the only issue is i getting corrupted when nr < 0;