From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [RFC v2 1/4] bridge: enable interfaces to opt out
 from becoming the root bridge
Date: Wed, 19 Feb 2014 09:08:55 -0800
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To: "Luis R. Rodriguez" <mcgrof@do-not-panic.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>, kvm@vger.kernel.org, "netdev@vger.kernel.org" <netdev@vger.kernel.org>, bridge@lists.linux-foundation.org, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Zoltan Kiss <zoltan.kiss@citrix.com>, xen-devel@lists.xenproject.org
List-Id: xen-devel@lists.xenproject.org

On Wed, 19 Feb 2014 09:02:06 -0800
"Luis R. Rodriguez" <mcgrof@do-not-panic.com> wrote:

> Folks, what if I repurpose my patch to use the IFF_BRIDGE_NON_ROOT (or
> relabel to IFF_ROOT_BLOCK_DEF) flag for a default driver preference
> upon initialization so that root block will be used once the device
> gets added to a bridge. The purpose would be to avoid drivers from
> using the high MAC address hack, streamline to use a random MAC
> address thereby avoiding the possible duplicate address situation for
> IPv6. In the STP use case for these interfaces we'd just require
> userspace to unset the root block. I'd consider the STP use case the
> most odd of all. The caveat to this approach is 3.8 would be needed
> (or its the root block patches cherry picked) for base kernels older
> than 3.8.
> 
> Stephen?
> 
>   Luis

Don't add IFF_ flags that adds yet another API hook into bridge.
Please only use the netlink/sysfs flags fields that already exist
for new features.