From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753831AbaFGBrY (ORCPT ); Fri, 6 Jun 2014 21:47:24 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35930 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752472AbaFGBXg (ORCPT ); Fri, 6 Jun 2014 21:23:36 -0400 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, "Tobias Brunner" , "Florian Westphal" , "David S. Miller" , "Eric Dumazet" Date: Sat, 07 Jun 2014 02:26:28 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 08/92] net: core: don't account for udp header size when computing seglen In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal [ Upstream commit 6d39d589bb76ee8a1c6cde6822006ae0053decff ] In case of tcp, gso_size contains the tcpmss. For UFO (udp fragmentation offloading) skbs, gso_size is the fragment payload size, i.e. we must not account for udp header size. Otherwise, when using virtio drivers, a to-be-forwarded UFO GSO packet will be needlessly fragmented in the forward path, because we think its individual segments are too large for the outgoing link. Fixes: fe6cc55f3a9a053 ("net: ip, ipv6: handle gso skbs in forwarding path") Cc: Eric Dumazet Reported-by: Tobias Brunner Signed-off-by: Florian Westphal Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/core/skbuff.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 8ac4a0f..8ae2e43 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3197,12 +3197,14 @@ EXPORT_SYMBOL(__skb_warn_lro_forwarding); unsigned int skb_gso_transport_seglen(const struct sk_buff *skb) { const struct skb_shared_info *shinfo = skb_shinfo(skb); - unsigned int hdr_len; if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) - hdr_len = tcp_hdrlen(skb); - else - hdr_len = sizeof(struct udphdr); - return hdr_len + shinfo->gso_size; + return tcp_hdrlen(skb) + shinfo->gso_size; + + /* UFO sets gso_size to the size of the fragmentation + * payload, i.e. the size of the L4 (UDP) header is already + * accounted for. + */ + return shinfo->gso_size; } EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);