Re: [PATCH net-next v2 3/3] net: ethtool: Remove PHYLIB direct dependency

On Mon, Jul 06, 2020 at 09:56:03PM +0200, Andrew Lunn wrote:

On Mon, Jul 06, 2020 at 11:40:00AM -0700, Jakub Kicinski wrote:

quoted

On Sun,  5 Jul 2020 21:27:58 -0700 Florian Fainelli wrote:

quoted

+	ops = ethtool_phy_ops;
+	if (!ops || !ops->start_cable_test) {

nit: don't think member-by-member checking is necessary. We don't
expect there to be any alternative versions of the ops, right?

I would not like to see anything else registering an ops. So i think
taking an Opps would be a good indication somebody is doing something
wrong and needs fixing.

quoted

We could even risk a direct call:

#if IS_REACHABLE(CONFIG_PHYLIB)
static inline int do_x()
{
	return __do_x();
}
#else
static inline int do_x()
{
	if (!ops)
		return -EOPNOTSUPP;
	return ops->do_x();
}
#endif

But that's perhaps doing too much...

I would say it is too far. Two ways of doing the same thing requires
twice as much testing. And these are not hot paths where we want to
eliminate as many instructions and trampolines as possible.

Agreed, it seems a bit over the top.

Michal