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

[Jakub Kicinski]

On Thu, 2 Jul 2020 18:34:24 +0200 Andrew Lunn wrote:
> 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().

+1