Subject: Re: [RFC PATCH 2/3] netdev: kernel-only IFF_HIDDEN netdevice

From: Andrew Lunn <[email-masked]>
Date: Tue, 10 Apr 2018 00:15:23 +0200

> No, implementation wise I'd avoid changing the class on the fly. What
> I'm looking to is a means to add a secondary class or class aliasing
> mechanism for netdevs that allows mapping for a kernel device
> namespace (/class/net-kernel) to userspace (/class/net). Imagine
> creating symlinks between these two namespaces as an analogy. All
> userspace visible netdevs today will have both a kernel name and a
> userspace visible name, having one (/class/net) referecing the other
> (/class/net-kernel) in its own namespace. The newly introduced
> IFF_AUTO_MANAGED device will have a kernel name only
> (/class/net-kernel). As a result, the existing applications using
> /class/net don't break, while we're adding the kernel namespace that
> allows IFF_AUTO_MANAGED devices which will not be exposed to userspace
> at all.

My gut feeling is this whole scheme will not fly. You really should be
talking to GregKH.

Anyway, please remember that IFF_AUTO_MANAGED will need to be dynamic.
A device can start out as a normal device, and will change to being
automatic later, when the user on top of it probes.

	Andrew