Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964982Ab1C3VIm (ORCPT ); Wed, 30 Mar 2011 17:08:42 -0400 Received: from mga11.intel.com ([192.55.52.93]:33607 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933368Ab1C3VIg (ORCPT ); Wed, 30 Mar 2011 17:08:36 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.63,270,1299484800"; d="scan'208";a="903735749" From: Andi Kleen References: <20110330203.501921634@firstfloor.org> In-Reply-To: <20110330203.501921634@firstfloor.org> To: Ian.Campbell@citrix.com, ian.campbell@citrix.com, davem@davemloft.net, ak@linux.intel.com, haiyangz@microsoft.com, mike@surcouf.co.uk, hjanssen@microsoft.com, gregkh@suse.de, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com Subject: [PATCH] [171/275] arp_notify: unconditionally send gratuitous ARP for NETDEV_NOTIFY_PEERS. Message-Id: <20110330210653.C01543E1A05@tassilo.jf.intel.com> Date: Wed, 30 Mar 2011 14:06:53 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2931 Lines: 90 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Ian Campbell commit d11327ad6695db8117c78d70611e71102ceec2ac upstream. NETDEV_NOTIFY_PEER is an explicit request by the driver to send a link notification while NETDEV_UP/NETDEV_CHANGEADDR generate link notifications as a sort of side effect. In the later cases the sysctl option is present because link notification events can have undesired effects e.g. if the link is flapping. I don't think this applies in the case of an explicit request from a driver. This patch makes NETDEV_NOTIFY_PEER unconditional, if preferred we could add a new sysctl for this case which defaults to on. This change causes Xen post-migration ARP notifications (which cause switches to relearn their MAC tables etc) to be sent by default. Signed-off-by: Ian Campbell Signed-off-by: David S. Miller Signed-off-by: Andi Kleen [reported to solve hyperv live migration problem - gkh] Cc: Haiyang Zhang Cc: Mike Surcouf Cc: Hank Janssen Signed-off-by: Greg Kroah-Hartman --- net/ipv4/devinet.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) Index: linux-2.6.35.y/net/ipv4/devinet.c =================================================================== --- linux-2.6.35.y.orig/net/ipv4/devinet.c 2011-03-29 22:50:55.819830128 -0700 +++ linux-2.6.35.y/net/ipv4/devinet.c 2011-03-29 23:03:01.802254055 -0700 @@ -1029,6 +1029,21 @@ return mtu >= 68; } +static void inetdev_send_gratuitous_arp(struct net_device *dev, + struct in_device *in_dev) + +{ + struct in_ifaddr *ifa = in_dev->ifa_list; + + if (!ifa) + return; + + arp_send(ARPOP_REQUEST, ETH_P_ARP, + ifa->ifa_address, dev, + ifa->ifa_address, NULL, + dev->dev_addr, NULL); +} + /* Called only under RTNL semaphore */ static int inetdev_event(struct notifier_block *this, unsigned long event, @@ -1081,18 +1096,13 @@ } ip_mc_up(in_dev); /* fall through */ - case NETDEV_NOTIFY_PEERS: case NETDEV_CHANGEADDR: + if (!IN_DEV_ARP_NOTIFY(in_dev)) + break; + /* fall through */ + case NETDEV_NOTIFY_PEERS: /* Send gratuitous ARP to notify of link change */ - if (IN_DEV_ARP_NOTIFY(in_dev)) { - struct in_ifaddr *ifa = in_dev->ifa_list; - - if (ifa) - arp_send(ARPOP_REQUEST, ETH_P_ARP, - ifa->ifa_address, dev, - ifa->ifa_address, NULL, - dev->dev_addr, NULL); - } + inetdev_send_gratuitous_arp(dev, in_dev); break; case NETDEV_DOWN: ip_mc_down(in_dev); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/