Re: [GIT] Networking

Rasmus Villemoes
2015-10-28T14:27:48Z

On Wed, Oct 28 2015, Hannes Frederic Sowa <hannes@stressinduktion.org> wrote:

> Hi Linus,
>
> On Wed, Oct 28, 2015, at 10:39, Linus Torvalds wrote:
>> Get rid of it. And I don't *ever* want to see that shit again.
>
> I don't want to give up on that this easily:
>
> In future I would like to see an interface like this. It is often hard
> to do correct overflow/wrap-around tests and it would be great if there
> are helper functions which could easily and without a lot of thinking be
> used by people to remove those problems from the kernel.

I agree - proper overflow checking can be really hard. Quick, assuming a
and b have the same unsigned integer type, is 'a+b<a' sufficient to
check overflow? Of course not (hint: promotion rules). And as you say,
it gets even more complicated for signed types.

A few months ago I tried posting a complete set of fallbacks for older
compilers (https://lkml.org/lkml/2015/7/19/358), but nothing really
happened. Now I know where Linus stands, so I guess I can just delete
that branch.

Rasmus