From: Jason Gunthorpe <jgg@mellanox.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Jonathan Toppins <jtoppins@redhat.com>,
Doug Ledford <dledford@redhat.com>,
RDMA mailing list <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH rdma-core] kernel-boot: Tighten check if device is virtual
Date: Thu, 3 Oct 2019 16:31:32 +0000 [thread overview]
Message-ID: <20191003163127.GE26151@mellanox.com> (raw)
In-Reply-To: <20190928165416.GL14368@unreal>
On Sat, Sep 28, 2019 at 07:54:16PM +0300, Leon Romanovsky wrote:
> On Thu, Sep 26, 2019 at 01:58:38PM -0400, Jonathan Toppins wrote:
> > On 09/26/2019 08:34 AM, Jason Gunthorpe wrote:
> > > On Thu, Sep 26, 2019 at 12:42:53PM +0300, Leon Romanovsky wrote:
> > >> From: Leon Romanovsky <leonro@mellanox.com>
> > >>
> > >> Virtual devices like SIW or RXE don't set FW version because
> > >> they don't have one, use that fact to rely on having empty
> > >> fw_ver file to sense such virtual devices.
> > >
> > > Have you checked that every physical device does set fw version?
> > >
> > > Seems hacky
> >
> > agreed, how are tuntap devices handled, is there a similar handling that
> > can be applied here?
>
> Unfortunately, we can't do the same, RDMA doesn't have notion of stacked devices.
>
> 1.
> TUN devices are initialized with ARPHRD_NONE type.
> https://elixir.bootlin.com/linux/latest/source/drivers/net/tun.c#L1396
>
> It causes for systemd-udev to skip their rename.
> https://github.com/systemd/systemd/blob/master/src/udev/udev-builtin-net_id.c#L781
>
> 2.
> TAP devices are skipped due to the fact that iflink != ifindex on such devices.
> https://github.com/systemd/systemd/blob/master/src/udev/udev-builtin-net_id.c#L810
>
> So, yes hacky, but the solution is tailored to RDMA subsystem where ALL
> devices have FW and we can ensure that ALL future devices will report any
> sort of string through fw_ver file.
It still seems really hacky, why not add some device flag or something
instead? Is this better because it works with old kernels?
Jason
next prev parent reply other threads:[~2019-10-03 16:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 9:42 [PATCH rdma-core] kernel-boot: Tighten check if device is virtual Leon Romanovsky
2019-09-26 12:29 ` Leon Romanovsky
2019-09-26 12:34 ` Jason Gunthorpe
2019-09-26 12:42 ` Leon Romanovsky
2019-09-26 17:58 ` Jonathan Toppins
2019-09-28 16:54 ` Leon Romanovsky
2019-10-03 16:31 ` Jason Gunthorpe [this message]
2019-10-05 6:12 ` Leon Romanovsky
2019-10-02 11:47 ` Leon Romanovsky
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