From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [RFC v2 1/4] bridge: enable interfaces to opt out from becoming the root bridge Date: Sun, 16 Feb 2014 10:57:54 -0800 Message-ID: <20140216105754.63738163@nehalam.linuxnetplumber.net> References: <1392433180-16052-1-git-send-email-mcgrof@do-not-panic.com> <1392433180-16052-2-git-send-email-mcgrof@do-not-panic.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, netdev@vger.kernel.org, "Luis R. Rodriguez" , bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org To: "Luis R. Rodriguez" Return-path: In-Reply-To: <1392433180-16052-2-git-send-email-mcgrof@do-not-panic.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: bridge-bounces@lists.linux-foundation.org Errors-To: bridge-bounces@lists.linux-foundation.org List-Id: kvm.vger.kernel.org On Fri, 14 Feb 2014 18:59:37 -0800 "Luis R. Rodriguez" wrote: > From: "Luis R. Rodriguez" > > It doesn't make sense for some interfaces to become a root bridge > at any point in time. One example is virtual backend interfaces > which rely on other entities on the bridge for actual physical > connectivity. They only provide virtual access. > > Device drivers that know they should never become part of the > root bridge have been using a trick of setting their MAC address > to a high broadcast MAC address such as FE:FF:FF:FF:FF:FF. Instead > of using these hacks lets the interfaces annotate its intent and > generalizes a solution for multiple drivers, while letting the > drivers use a random MAC address or one prefixed with a proper OUI. > This sort of hack is used by both qemu and xen for their backend > interfaces. > > Cc: Stephen Hemminger > Cc: bridge@lists.linux-foundation.org > Cc: netdev@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Luis R. Rodriguez This is already supported in a more standard way via the root block flag.