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Date: Sat, 24 Mar 2018 10:01:37 -0700
From: Richard Cochran <richardcochran@gmail.com>
Subject: Re: [PATCH net-next RFC V1 3/5] net: Introduce field for the MII
 time stamper.
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To: Florian Fainelli <f.fainelli@gmail.com>
Cc: netdev@vger.kernel.org, devicetree@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>, David Miller <davem@davemloft.net>, Mark Rutland <mark.rutland@arm.com>, Miroslav Lichvar <mlichvar@redhat.com>, Rob Herring <robh+dt@kernel.org>, Willem de Bruijn <willemb@google.com>
List-ID: <devicetree@vger.kernel.org>

On Wed, Mar 21, 2018 at 12:12:00PM -0700, Florian Fainelli wrote:
> > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> > index 5fbb9f1da7fd..223d691aa0b0 100644
> > --- a/include/linux/netdevice.h
> > +++ b/include/linux/netdevice.h
> > @@ -1943,6 +1943,7 @@ struct net_device {
> >  	struct netprio_map __rcu *priomap;
> >  #endif
> >  	struct phy_device	*phydev;
> > +	struct mdio_device	*mdiots;
> 
> phy_device embedds a mdio_device, can you find a way to rework the PHY
> PTP code to utilize the phy_device's mdio instance so do not introduce
> yet another pointer in that big structure that net_device already is?

You are right in that this field is wasted space for most users.

In V2 this will be inside #ifdef CONFIG_NETWORK_PHY_TIMESTAMPING.

Thanks,
Richard