From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jakub Kicinski <jakub.kicinski@netronome.com>
Subject: Re: [RFC] hv_netvsc: automatically name slave VF network device
Date: Tue, 19 Dec 2017 15:53:53 -0800
Message-ID: <20171219155353.4aa0fe9b@cakuba.netronome.com>
References: <20171219193537.22587-1-sthemmin@microsoft.com>
        <e2fa7512-7c49-b756-f239-8bf52bc70d65@intel.com>
        <20171219145017.78b60959@xeon-e3>
        <20171219152057.1e19a0bc@cakuba.netronome.com>
        <20171219154405.5bb35eff@xeon-e3>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Cc: "Samudrala, Sridhar" <sridhar.samudrala@intel.com>,
        netdev@vger.kernel.org, Stephen Hemminger <sthemmin@microsoft.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mail-qk0-f194.google.com ([209.85.220.194]:40737 "EHLO
        mail-qk0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1753375AbdLSXx6 (ORCPT
        <rfc822;netdev@vger.kernel.org>); Tue, 19 Dec 2017 18:53:58 -0500
Received: by mail-qk0-f194.google.com with SMTP id q14so11940348qke.7
        for <netdev@vger.kernel.org>; Tue, 19 Dec 2017 15:53:57 -0800 (PST)
In-Reply-To: <20171219154405.5bb35eff@xeon-e3>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On Tue, 19 Dec 2017 15:44:05 -0800, Stephen Hemminger wrote:
> On Tue, 19 Dec 2017 15:20:57 -0800
> Jakub Kicinski <jakub.kicinski@netronome.com> wrote:
>=20
> > On Tue, 19 Dec 2017 14:50:17 -0800, Stephen Hemminger wrote: =20
> > > On Tue, 19 Dec 2017 14:44:37 -0800
> > > "Samudrala, Sridhar" <sridhar.samudrala@intel.com> wrote:
> > >    =20
> > > >  -static void __netvsc_vf_setup(struct net_device *ndev,     =20
> > > > > -			      struct net_device *vf_netdev)
> > > > > -{
> > > > > -	int ret;
> > > > > +	/* set the name of VF device based on upper device name */
> > > > > +	snprintf(vf_name, IFNAMSIZ, "%s_vf", ndev->name);
> > > > > +	ret =3D dev_change_name(vf_netdev, vf_name);
> > > > > +	if (ret !=3D 0)
> > > > > +		netdev_warn(vf_netdev,
> > > > > +			    "can not rename device: (%d)\n", ret);       =20
> > > >=20
> > > > It is possible that upper device name can change after this call.=
=C2=A0 I=20
> > > > noticed this
> > > > when i tried this approach with virtio_net.
> > > >=20
> > > > Also, what should happen if the upper device is unloaded? Should we=
 rename
> > > > the VF name?     =20
> > >=20
> > > Yes upper device can change name. So sure, netdevice could trap that
> > > in callback (it already has notifier) and rename VF. Will add that in=
 V2.
> > >=20
> > > If upper device is unloaded then it is already decoupled from the VF.
> > > There is no good value to change it back to. The orignal name probably
> > > has been reused by then.   =20
> >=20
> > Both of those issues would be solved by just exposing phys_port_name
> > from the VF driver, and letting systemd do its thing independent of=20
> > magic bonds.
> >=20
> > Reluctance to do driver work aside :/ =20
>=20
> The port name for Mellanox driver is already set in the driver as a numer=
ic value.
> It indicates which port is used.
> This won't work.

You must be looking at representor ndos.  I don't think MLX NIC drivers
are implementing phys_port_name for normal netdevs at all today.