Re: [PATCH 6/7] pipe: simplify round_pipe_size()

Eric Biggers
2018-01-10T02:52:07Z

On Tue, Jan 09, 2018 at 02:27:10PM -0800, Kees Cook wrote:
>
> > @@ -1054,9 +1048,6 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
> > return -EINVAL;
> > nr_pages = size >> PAGE_SHIFT;
> >
> > - if (!nr_pages)
> > - return -EINVAL;
> > -
>
> I would just leave this hunk anyway: it's defensive for any future
> changes. Maybe add a comment describing why it's currently redundant?
>

I don't know; I find it really confusing to have two slightly different checks
for the same thing, as it implies that they actually need to be there for a
reason. How about just checking nr_pages?

size = round_pipe_size(arg);
nr_pages = size >> PAGE_SHIFT;

if (nr_pages == 0)
return -EINVAL;

Eric