Re: [PATCH v5 3/3] overflow: Introduce wrapping_inc() and wrapping_dec()

[Andy Shevchenko]

On Wed, Feb 07, 2024 at 08:08:14AM -0800, Kees Cook wrote:
> On Wed, Feb 07, 2024 at 05:31:54PM +0200, Andy Shevchenko wrote:
> > On Wed, Feb 7, 2024 at 5:24 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > >
> > > This allows replacements of the idioms "var += offset" and "var -= offset"
> > > with the wrapping_inc() and wrapping_dec() helpers respectively. They
> > > will avoid wrap-around sanitizer instrumentation.
> > >
> > > Add to the selftests to validate behavior and lack of side-effects.
> > 
> > I would expect inc/dec to add/subtract 1. So, to me the terminology is
> > confusing. The list of the C/C++ operators on Wikipedia describes
> > above as
> > 
> > += Assignment by sum
> > -= Assignment by difference
> > 
> > Hence the proposal is to have
> > 
> > wrapping_sum()
> > wrapping_diff()
> 
> I think maybe the missing phrase is "assign", which is what makes
> argument 1 "special" -- it's being changed. Perhaps:
> 
> wrapping_add_assign()
> wrapping_sub_assign()
> 
> ?

WFM!

-- 
With Best Regards,
Andy Shevchenko