From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nikolay Aleksandrov <nikolay@redhat.com>
Subject: Re: [net-next,1/3] bonding: fix vlan 0 addition and removal
Date: Tue, 06 Aug 2013 10:39:22 +0200
Message-ID: <5200B63A.5070900@redhat.com>
References: <1375709304-16778-2-git-send-email-nikolay@redhat.com> <20130805215126.GB3859@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: netdev@vger.kernel.org, fubar@us.ibm.com, andy@greyhouse.net,
	davem@davemloft.net, kaber@trash.net
To: Veaceslav Falico <vfalico@redhat.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mx1.redhat.com ([209.132.183.28]:32712 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1753526Ab3HFIja (ORCPT <rfc822;netdev@vger.kernel.org>);
	Tue, 6 Aug 2013 04:39:30 -0400
In-Reply-To: <20130805215126.GB3859@redhat.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

> From 1c89abefebe90568ed52d2df59fcfdd650bc4696 Mon Sep 17 00:00:00 2001
> From: Veaceslav Falico <vfalico@redhat.com>
> Date: Mon, 5 Aug 2013 23:29:12 +0200
> Subject: [PATCH] bonding: add vlan_uses_dev_rcu() and make bond_vlan_used()
> use it
> 
> Currently, bond_vlan_used() looks for any vlan, including the pseudo-vlan
> id 0, and always returns true if 8021q is loaded. This creates several bad
> situations - some warnings in __bond_release_one() because it thinks that
> we still have vlans while removing, sending LB packets with vlan id 0 and,
> possibly, other caused by vlan id 0.
> 
> Fix it by adding a new call, vlan_uses_dev_rcu(), which is the same as
> vlan_uses_dev(), but uses rcu_dereference() instead of rtnl, and thus we
> can use it in bond_vlan_used() wrapped in rcu_read_lock().
> 
> Also, use the pure vlan_uses_dev() in __bond_release_one() cause the rtnl
> lock is held there.
> 
Just 1 more note, you can't trust nr_vlan_devs under RCU.