From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id Z05CCto9GVvtRQAAmS7hNA ; Thu, 07 Jun 2018 14:15:18 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 420BF608BF; Thu, 7 Jun 2018 14:15:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id A39A36063F; Thu, 7 Jun 2018 14:15:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A39A36063F Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753742AbeFGONv (ORCPT + 25 others); Thu, 7 Jun 2018 10:13:51 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:39538 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933162AbeFGOJj (ORCPT ); Thu, 7 Jun 2018 10:09:39 -0400 Received: from [148.252.241.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1fQvbJ-0005Zo-9I; Thu, 07 Jun 2018 15:09:17 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1fQvbF-0003IX-04; Thu, 07 Jun 2018 15:09:13 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Ido Schimmel" , "David S. Miller" , "Petr Machata" Date: Thu, 07 Jun 2018 15:05:21 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 393/410] ip_tunnel: Emit events for post-register MTU changes In-Reply-To: X-SA-Exim-Connect-IP: 148.252.241.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.57-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Petr Machata commit f6cc9c054e77b9a28d4594bcc201697edb21dfd2 upstream. For tunnels created with IFLA_MTU, MTU of the netdevice is set by rtnl_create_link() (called from rtnl_newlink()) before the device is registered. However without IFLA_MTU that's not done. rtnl_newlink() proceeds by calling struct rtnl_link_ops.newlink, which via ip_tunnel_newlink() calls register_netdevice(), and that emits NETDEV_REGISTER. Thus any listeners that inspect the netdevice get the MTU of 0. After ip_tunnel_newlink() corrects the MTU after registering the netdevice, but since there's no event, the listeners don't get to know about the MTU until something else happens--such as a NETDEV_UP event. That's not ideal. So instead of setting the MTU directly, go through dev_set_mtu(), which takes care of distributing the necessary NETDEV_PRECHANGEMTU and NETDEV_CHANGEMTU events. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Petr Machata Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller [bwh: Backported to 3.16: Resolve conflict with commit 24fc79798b8d "ip_tunnel: Clamp MTU to bounds on new link", referring to commit 5568cdc368c3 "ip_tunnel: Resolve ipsec merge conflict properly."] Signed-off-by: Ben Hutchings --- --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -405,17 +405,26 @@ static struct ip_tunnel *ip_tunnel_creat { struct ip_tunnel *nt; struct net_device *dev; + int mtu; + int err; BUG_ON(!itn->fb_tunnel_dev); dev = __ip_tunnel_create(net, itn->fb_tunnel_dev->rtnl_link_ops, parms); if (IS_ERR(dev)) return ERR_CAST(dev); - dev->mtu = ip_tunnel_bind_dev(dev); + mtu = ip_tunnel_bind_dev(dev); + err = dev_set_mtu(dev, mtu); + if (err) + goto err_dev_set_mtu; nt = netdev_priv(dev); ip_tunnel_add(itn, nt); return nt; + +err_dev_set_mtu: + unregister_netdevice(dev); + return ERR_PTR(err); } int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb, @@ -962,7 +971,7 @@ int ip_tunnel_newlink(struct net_device nt->parms = *p; err = register_netdevice(dev); if (err) - goto out; + goto err_register_netdevice; if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS]) eth_hw_addr_random(dev); @@ -971,15 +980,20 @@ int ip_tunnel_newlink(struct net_device if (tb[IFLA_MTU]) { unsigned int max = 0xfff8 - dev->hard_header_len - nt->hlen; - dev->mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU, - (unsigned int)(max - sizeof(struct iphdr))); - } else { - dev->mtu = mtu; + mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU, + (unsigned int)(max - sizeof(struct iphdr))); } + err = dev_set_mtu(dev, mtu); + if (err) + goto err_dev_set_mtu; + ip_tunnel_add(itn, nt); + return 0; -out: +err_dev_set_mtu: + unregister_netdevice(dev); +err_register_netdevice: return err; } EXPORT_SYMBOL_GPL(ip_tunnel_newlink);