Re: [PATCH net-next 00/19] Mellanox, mlx5 sub function support

[Leon Romanovsky <leon@kernel.org>]

On Thu, Nov 07, 2019 at 08:10:45PM +0000, Parav Pandit wrote:
> Hi Leon,
>
> > -----Original Message-----
> > From: Leon Romanovsky <leon@kernel.org>
> > Sent: Thursday, November 7, 2019 11:04 AM
> > To: Parav Pandit <parav@mellanox.com>
> > Cc: alex.williamson@redhat.com; davem@davemloft.net;
> > kvm@vger.kernel.org; netdev@vger.kernel.org; Saeed Mahameed
> > <saeedm@mellanox.com>; kwankhede@nvidia.com; cohuck@redhat.com; Jiri
> > Pirko <jiri@mellanox.com>; linux-rdma@vger.kernel.org
> > Subject: Re: [PATCH net-next 00/19] Mellanox, mlx5 sub function support
> >
> > On Thu, Nov 07, 2019 at 10:04:48AM -0600, Parav Pandit wrote:
> > > Hi Dave, Jiri, Alex,
> > >
> >
> > <...>
> >
> > > - View netdevice and (optionally) RDMA device using iproute2 tools
> > >     $ ip link show
> > >     $ rdma dev show
> >
> > You perfectly explained how ETH devices will be named, but what about
> > RDMA?
> > How will be named? I feel that rdma-core needs to be extended to support such
> > mediated devices.
> >
> rdma devices are named by default using mlx_X.
> After your persistent naming patches, I thought we have GUID based naming scheme which doesn't care about its underlying bus.

No, it is not how it is done. RDMA persistent naming is modeled exactly
as ETH naming, it means that we do care about bus and we don't use GUID
unless user explicitly asked, exactly as MAC based names in ETH world.

> So mdevs will be able to use current GUID based naming scheme we already have.

Unfortunately, no.

>
> Additionally, if user prefers, mdev alias, we can extend systemd/udev to use mdev alias based names (like PCI bdf).

It is not "Additionally", but "must".

> Such as,
> rocem<alias1>
> ibm<alias2>
> Format is:
> <link_layer><m><alias>
> m -> stands for mdev device (similar to 'p' for PCI)