Re: [PATCH net-next 0/4] net: ethtool: Untangle PHYLIB dependency

[Andrew Lunn <andrew@lunn.ch>]

On Thu, Jul 02, 2020 at 05:56:52PM +0200, Michal Kubecek wrote:
> On Wed, Jul 01, 2020 at 09:29:38PM -0700, Florian Fainelli wrote:
> > Hi all,
> > 
> > This patch series untangles the ethtool netlink dependency with PHYLIB
> > which exists because the cable test feature calls directly into PHY
> > library functions. The approach taken here is to utilize a new set of
> > net_device_ops function pointers which are automatically set to the PHY
> > library variants when a network device driver attaches to a PHY device.
> 
> I'm not sure about the idea of creating a copy of netdev_ops for each
> device using phylib. First, there would be some overhead (just checked
> my 5.8-rc3 kernel, struct netdev_ops is 632 bytes). Second, there is
> quite frequent pattern of comparing dev->netdev_ops against known
> constants to check if a network device is of certain type; I can't say
> for sure if it is also used with devices using phylib in existing code
> but it feels risky.

I agree with Michal here. I don't like this.

I think we need phylib to register a set of ops with ethtool when it
loads. It would also allow us to clean up phy_ethtool_get_strings(),
phy_ethtool_get_sset_count(), phy_ethtool_get_stats().

      Andrew