Proposed F19 Feature: systemd/udev Predictable Network Interface Names

[Narendra_K at Dell.com]

> -----Original Message-----
> From: devel-bounces at lists.fedoraproject.org [mailto:devel-
> bounces at lists.fedoraproject.org] On Behalf Of Michal Schmidt
> Sent: Tuesday, March 05, 2013 10:22 PM
> To: devel at lists.fedoraproject.org
> Subject: Re: Proposed F19 Feature: systemd/udev Predictable Network
> Interface Names
> 
> On 03/04/2013 04:01 PM, Matt Domsch wrote:
> > drivers/net/ethernet/sfc/siena.c:       efx->net_dev->dev_id =
> EFX_OWORD_FIELD(reg, FRF_CZ_CS_PORT_NUM) - 1;
> 
> I think sfc does not really *need* to set dev_id.
> Yes, these are multi-port cards, but the ports are on distinct PCI functions.
> 

I think setting of 'dev_id' by drivers/devices used in enterprise server environment will be beneficial, not just for devices in which multiple ports share a single PCI d/b/d/f("1 PCI d/b/d/f -> 2 ports"),  also for  multiport devices with   "1 PCI d/b/d/f -> 1 Port" mapping.  The following scenarios demonstrate the requirement/usefulness -

1.  As the dev_id would indicate the physical port number used by a netdevice and will be available to user space via sysfs, tools such as NetworkManager could use the information to implement intelligent/smarter bonding of netdevices. For example, when bonding netdevices coming from NIC partitions (or SR-IOV VFs) which use the same physical port, in fault tolerance mode for example, NM could inform the user that the netdevices  being enslaved map to/use the same physical port and  bonding them may not have desired effect. Dev_id would provide such information in a generic way.

2. biosdevname could possibly use 'dev_id' to determine the <port> part of p<slot>p<port> eliminating the need to determine/enumerate port number as pointed out here.

With regards,
Narendra K