Re: [RFC net-next 0/4] ethtool: CMIS module diagnostic loopback support

[Andrew Lunn]

> > Suddenly does something else.
> 
> Indeed!
> 
> > Is this an ABI break? How do we make this reliable so implementing
> > more loopbacks at different levels does not change how you use
> > --set-loopback?
> 
> Isn't this somewhat similar to what we have with ifindex/phy_index,
> but potentially unstable when modules are swapped/changed?

If you hot plug hardware, a new PHY pops into existence, i don't think
it is too unreasonable for the hot plugable parts to change ids. I
would however expect the fixed parts to keep there IDs.

But here we are talking about software, a kernel upgrade/downgrade
causing the IDs to change.
 
> Instead of ids, use string name and/or topology indices (e.g.
> phy_index)? All three -- owner, phy_index, name tuple?

Probably.

	Andrew