Re: [PATCH] aio: Cleanup unnecessary test for nr_pages

From: Al Viro
Date: Mon Jun 20 2016 - 10:20:21 EST


On Mon, Jun 20, 2016 at 10:05:45PM +0800, Minfei Huang wrote:
> Ping. Any comment is appreciate.
>
> Thanks
> Minfei
>
> On 06/13/16 at 12:33P, Minfei Huang wrote:
> > The variable nr_pages is always more than 1, because the size of
> > structure aio_ring is bigger than 0. So remove unnecessary test for
> > nr_page.

What this test really checks is that the value we'd put into nr_pages
(PFN_UP(size)) is not greater than 2^31. Whether it's redundant or not
is a separate question - it very well might be, due to the code in
ioctx_alloc() that caps nr_events, but that needs a proof. In any case,
the reasons you are offering in commit message are wrong - it's about
size being too _large_, not too small.