Re: [PATCH 01/20] ethernet: ucc_geth: set dev->max_mtu to 1518

From: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>
To: "andrew@lunn.ch" <andrew@lunn.ch>
Cc: "rasmus.villemoes@prevas.dk" <rasmus.villemoes@prevas.dk>,
	"leoyang.li@nxp.com" <leoyang.li@nxp.com>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"murali.policharla@broadcom.com" <murali.policharla@broadcom.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"vladimir.oltean@nxp.com" <vladimir.oltean@nxp.com>,
	"kuba@kernel.org" <kuba@kernel.org>,
	"f.fainelli@gmail.com" <f.fainelli@gmail.com>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"qiang.zhao@nxp.com" <qiang.zhao@nxp.com>
Subject: Re: [PATCH 01/20] ethernet: ucc_geth: set dev->max_mtu to 1518
Date: Tue, 5 Jan 2021 14:44:31 +0000	[thread overview]
Message-ID: <6c56889ce3d0e9fc7a6ca7e7a43091b1ae8cd309.camel@infinera.com> (raw)
In-Reply-To: <X/R4tqny72Bjt28b@lunn.ch>

On Tue, 2021-01-05 at 15:33 +0100, Andrew Lunn wrote:
> On Tue, Jan 05, 2021 at 02:17:42PM +0000, Joakim Tjernlund wrote:
> > On Thu, 2020-12-10 at 02:25 +0100, Andrew Lunn wrote:
> > > On Sat, Dec 05, 2020 at 08:17:24PM +0100, Rasmus Villemoes wrote:
> > > > All the buffers and registers are already set up appropriately for an
> > > > MTU slightly above 1500, so we just need to expose this to the
> > > > networking stack. AFAICT, there's no need to implement .ndo_change_mtu
> > > > when the receive buffers are always set up to support the max_mtu.
> > > > 
> > > > This fixes several warnings during boot on our mpc8309-board with an
> > > > embedded mv88e6250 switch:
> > > > 
> > > > mv88e6085 mdio@e0102120:10: nonfatal error -34 setting MTU 1500 on port 0
> > > > ...
> > > > mv88e6085 mdio@e0102120:10: nonfatal error -34 setting MTU 1500 on port 4
> > > > ucc_geth e0102000.ethernet eth1: error -22 setting MTU to 1504 to include DSA overhead
> > > > 
> > > > The last line explains what the DSA stack tries to do: achieving an MTU
> > > > of 1500 on-the-wire requires that the master netdevice connected to
> > > > the CPU port supports an MTU of 1500+the tagging overhead.
> > > > 
> > > > Fixes: bfcb813203e6 ("net: dsa: configure the MTU for switch ports")
> > > > Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
> > > > Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
> > > 
> > > Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> > > 
> > >     Andrew
> > 
> > I don't see this in any kernel, seems stuck? Maybe because the series as a whole is not approved?
> 
> Hi Joakim
> 
> When was it posted? If it was while netdev was closed during the merge
> window, you need to repost.
> 
> You should be able to see the status in the netdev patchwork instance
> 
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fproject%2Fnetdevbpf%2Flist%2F&amp;data=04%7C01%7CJoakim.Tjernlund%40infinera.com%7C25615f4c00a44959810208d8b186e496%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C0%7C637454540217112252%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=00l%2FBYyxnAoshH1aZMwEznVFQZXwaYGe3pTo6R3RG3Q%3D&amp;reserved=0
> 
> 	Andrew

Hi Andrew

I found here: 
https://patchwork.kernel.org/project/netdevbpf/patch/20201218105538.30563-2-rasmus.villemoes@prevas.dk/

Seem to be underway but stable isn't included, I think it should be.

 Jocke