From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Tobias Brunner , Florian Westphal , "David S. Miller" Subject: [PATCH 3.10 42/86] net: core: dont account for udp header size when computing seglen Date: Wed, 28 May 2014 21:37:17 -0700 Message-Id: <20140529043519.201231466@linuxfoundation.org> In-Reply-To: <20140529043513.451722422@linuxfoundation.org> References: <20140529043513.451722422@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable 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: Greg Kroah-Hartman --- net/core/skbuff.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3487,12 +3487,14 @@ EXPORT_SYMBOL(skb_try_coalesce); 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);