From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752809AbcFVXT6 (ORCPT ); Wed, 22 Jun 2016 19:19:58 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46250 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752266AbcFVWls (ORCPT ); Wed, 22 Jun 2016 18:41:48 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Wragg , "David S. Miller" Subject: [PATCH 4.4 20/75] geneve: Relax MTU constraints Date: Wed, 22 Jun 2016 15:40:42 -0700 Message-Id: <20160622223501.070361464@linuxfoundation.org> X-Mailer: git-send-email 2.9.0 In-Reply-To: <20160622223500.055133765@linuxfoundation.org> References: <20160622223500.055133765@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Wragg [ Upstream commit 55e5bfb53cff286c1c1ff49f51325dc15c7fea63 ] Allow the MTU of geneve devices to be set to large values, in order to exploit underlying networks with larger frame sizes. GENEVE does not have a fixed encapsulation overhead (an openvswitch rule can add variable length options), so there is no relevant maximum MTU to enforce. A maximum of IP_MAX_MTU is used instead. Encapsulated packets that are too big for the underlying network will get dropped on the floor. Signed-off-by: David Wragg Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/geneve.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -994,6 +994,17 @@ static netdev_tx_t geneve_xmit(struct sk return geneve_xmit_skb(skb, dev, info); } +static int geneve_change_mtu(struct net_device *dev, int new_mtu) +{ + /* GENEVE overhead is not fixed, so we can't enforce a more + * precise max MTU. + */ + if (new_mtu < 68 || new_mtu > IP_MAX_MTU) + return -EINVAL; + dev->mtu = new_mtu; + return 0; +} + static int geneve_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb) { struct ip_tunnel_info *info = skb_tunnel_info(skb); @@ -1038,7 +1049,7 @@ static const struct net_device_ops genev .ndo_stop = geneve_stop, .ndo_start_xmit = geneve_xmit, .ndo_get_stats64 = ip_tunnel_get_stats64, - .ndo_change_mtu = eth_change_mtu, + .ndo_change_mtu = geneve_change_mtu, .ndo_validate_addr = eth_validate_addr, .ndo_set_mac_address = eth_mac_addr, .ndo_fill_metadata_dst = geneve_fill_metadata_dst,