[PATCH net-next 12/13] net: phy: phylink: Use phy_caps_lookup for fixed-link configuration

[Russell King (Oracle)]

On Mon, Feb 24, 2025 at 02:44:31PM +0100, Kory Maincent wrote:
> On Sat, 22 Feb 2025 15:27:24 +0100
> Maxime Chevallier <maxime.chevallier at bootlin.com> wrote:
> 
> > When phylink creates a fixed-link configuration, it finds a matching
> > linkmode to set as the advertised, lp_advertising and supported modes
> > based on the speed and duplex of the fixed link.
> > 
> > Use the newly introduced phy_caps_lookup to get these modes instead of
> > phy_lookup_settings(). This has the side effect that the matched
> > settings and configured linkmodes may now contain several linkmodes (the
> > intersection of supported linkmodes from the phylink settings and the
> > linkmodes that match speed/duplex) instead of the one from
> > phy_lookup_settings().
> 
> ...
> 
> >  
> >  	linkmode_set_bit(ETHTOOL_LINK_MODE_Pause_BIT, mask);
> >  	linkmode_set_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, mask);
> > @@ -588,9 +591,9 @@ static int phylink_parse_fixedlink(struct phylink *pl,
> >  
> >  	phylink_set(pl->supported, MII);
> >  
> > -	if (s) {
> > -		__set_bit(s->bit, pl->supported);
> > -		__set_bit(s->bit, pl->link_config.lp_advertising);
> > +	if (c) {
> > +		linkmode_or(pl->supported, pl->supported, match);
> > +		linkmode_or(pl->link_config.lp_advertising,
> > pl->supported, match);
> 
> You are doing the OR twice. You should use linkmode_copy() instead.

No, we don't want to copy pl->supported to
pl->link_config.lp_advertising. We just want to set the linkmode bit
that corresponds to the speed/duplex in each mask.

That will result in e.g. the pause mode bits will be overwritten despite
being appropriately set in the advertising mask in the code above this.

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