[PATCH 2/2] iproute2: add support for link set

[Rui Salvaterra]

Hi, Ansuel,

On Sat, 22 Jan 2022 at 01:08, Ansuel Smith <ansuelsmth at gmail.com> wrote:
>
>
> So.. how should we proceed with this? From what I understand the idea is to merge this ASAP.

But not a moment sooner. ;) I'm sure we agree that this patch won't be
merged upstream in its current form, according to the comments
received, and the less we diverge from upstream, the better for
maintenance.

> Think we have to change this with the DSA specific attribute.

Ok, let's step back and take a look at our possibilities. Stephen
Hemminger suggested auditing all kernel usage of IFLA_LINK and adding
checks where needed to make sure the current users don't break [1].
This would certainly work, but that would mean sprinkling error checks
in possibly quite a number of places [2]. Vladimir Oltean, instead,
suggested creating a new netlink attribute for this specific purpose
[3] (let's call it IFLA_CPU, for example). I believe the latter is the
less intrusive of the options, with the added bonus of not having to
overload IFLA_LINK with different semantics (something I personally
dislike). I would also rename "link" to "cpu" in the ip patch
(avoiding the overload, once again).

[1] https://lore.kernel.org/netdev/20210411100411.6d16e51d@hermes.local/
[2] https://elixir.bootlin.com/linux/latest/A/ident/IFLA_LINK
[3] https://lore.kernel.org/netdev/20210411170939.cxmva5vdcpqu4bmi@skbuf/

Cheers,
Rui