From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH 1/1] dev_change_net_namespace: send a KOBJ_REMOVED/KOBJ_ADD Date: Mon, 15 Oct 2012 22:14:17 +0200 Message-ID: <507C6E99.7090906@free.fr> References: <20121015174726.GA15435@sergelap> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Daniel Lezcano , containers@lists.linux-foundation.org, Stefan Bader , =?ISO-8859-1?Q?St=E9phane_Graber?= , "Eric W. Biederman" , Dan Kegel , lxc-users@lists.sourceforge.net To: Serge Hallyn Return-path: Received: from smtp1-g21.free.fr ([212.27.42.1]:48770 "EHLO smtp1-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932092Ab2JOUOh (ORCPT ); Mon, 15 Oct 2012 16:14:37 -0400 In-Reply-To: <20121015174726.GA15435@sergelap> Sender: netdev-owner@vger.kernel.org List-ID: On 10/15/2012 07:47 PM, Serge Hallyn wrote: > When a new nic is created in namespace ns1, the kernel sends a KOBJ_ADD uevent > to ns1. When the nic is moved to ns2, we only send a KOBJ_MOVE to ns2, and > nothing to ns1. > > This patch changes that behavior so that when moving a nic from ns1 to ns2, we > send a KOBJ_REMOVED to ns1 and KOBJ_ADD to ns2. (The KOBJ_MOVE is still > sent to ns2). > > The effects of this can be seen when starting and stopping containers in > an upstart based host. Lxc will create a pair of veth nics, the kernel > sends KOBJ_ADD, and upstart starts network-instance jobs for each. When > one nic is moved to the container, because no KOBJ_REMOVED event is > received, the network-instance job for that veth never goes away. This > was reported at https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1065589 > With this patch the networ-instance jobs properly go away. > > The other oddness solved here is that if a nic is passed into a running > upstart-based container, without this patch no network-instance job is > started in the container. But when the container creates a new nic > itself (ip link add new type veth) then network-interface jobs are > created. With this patch, behavior comes in line with a regular host. > > v2: also send KOBJ_ADD to new netns. There will then be a > _MOVE event from the device_rename() call, but that should > be innocuous. > > Signed-off-by: Serge Hallyn > Acked-by: "Eric W. Biederman" Acked-by: Daniel Lezcano > --- > net/core/dev.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/net/core/dev.c b/net/core/dev.c > index e2215ee..2c43aaf 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -6172,6 +6172,9 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char > dev_uc_flush(dev); > dev_mc_flush(dev); > > + /* Send a netdev-removed uevent to the old namespace */ > + kobject_uevent(&dev->dev.kobj, KOBJ_REMOVE); > + > /* Actually switch the network namespace */ > dev_net_set(dev, net); > > @@ -6183,6 +6186,9 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char > dev->iflink = dev->ifindex; > } > > + /* Send a netdev-add uevent to the new namespace */ > + kobject_uevent(&dev->dev.kobj, KOBJ_ADD); > + > /* Fixup kobjects */ > err = device_rename(&dev->dev, dev->name); > WARN_ON(err);