Re: [PATCH net v2] Revert "ipv6: preserve insertion order for same-scope addresses"

[Matthieu Baerts <matttbe@kernel.org>]

Hi Íñigo,

On 03/06/2026 16:53, Íñigo Huguet wrote:
> On Wed, Jun 3, 2026 at 7:46 AM Matthieu Baerts <matttbe@kernel.org> wrote:
>> I guess it is safer not to break UAPI and not reapplying the patch,
>> especially when there is no clear way to know which order is taken by
>> the kernel.
>>
>> What about clearly stating that the default order is "random", except
>> when an additional flag is set to sort them chronologically or the opposite?
> 
> Stating that the order is "random" implies that someone will change
> the default insertion order in the future, as the documentation says
> that it's not UAPI. So they'll cause the UAPI breakage that we are
> trying to avoid now. Moreover, if we consider the default order
> "random" and state that userspace programs must not rely on it, why
> can't we change it now?

I was only suggesting "random", simply to force userspace programs to
ask for a specific order when the order matters. But also to avoid
having to describe the current order, which is different in v4 and v6
for entries of the same scope.

I know the order is not random, and even if it is confusing, I don't
think we can change it without breaking stuff.

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.