Re: [RFC] hv_netvsc: automatically name slave VF network device

Wed, Dec 20, 2017 at 12:53:53AM CET, jakub.kicinski@netronome.com wrote:

On Tue, 19 Dec 2017 15:44:05 -0800, Stephen Hemminger wrote:

quoted

On Tue, 19 Dec 2017 15:20:57 -0800
Jakub Kicinski [off-list ref] wrote:

quoted

On Tue, 19 Dec 2017 14:50:17 -0800, Stephen Hemminger wrote:  

quoted

On Tue, 19 Dec 2017 14:44:37 -0800
"Samudrala, Sridhar" [off-list ref] wrote:
    

quoted

 -static void __netvsc_vf_setup(struct net_device *ndev,      

quoted

-			      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 = dev_change_name(vf_netdev, vf_name);
+	if (ret != 0)
+		netdev_warn(vf_netdev,
+			    "can not rename device: (%d)\n", ret);        

It is possible that upper device name can change after this call.  I 
noticed this
when i tried this approach with virtio_net.

Also, what should happen if the upper device is unloaded? Should we rename
the VF name?      

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.

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.    

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 
magic bonds.

Reluctance to do driver work aside :/  

The port name for Mellanox driver is already set in the driver as a numeric 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.

You are right Jakub. I plan to generate phys_port_name according to the
netdev flavours (vf,pf,qp,vfrep,pfrep,qprep,etc). That would resolve
this.