3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang <jasowang@xxxxxxxxxx> [ Upstream commit f9ca8f74399f9195fd8e01f67a8424a8d33efa55 ] Currently, for the packets receives from netback, before doing header check, kernel just reset the transport header in netif_receive_skb() which pretends non l4 header. This is suboptimal for precise packet length estimation (introduced in 1def9238: net_sched: more precise pkt_len computation) which needs correct l4 header for gso packets. The patch just reuse the header probed by netback for partial checksum packets and tries to use skb_flow_dissect() for other cases, if both fail, just pretend no l4 header. Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> Cc: Eric Dumazet <edumazet@xxxxxxxxxx> Cc: Ian Campbell <ian.campbell@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/xen-netback/netback.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -39,6 +39,7 @@ #include <linux/udp.h> #include <net/tcp.h> +#include <net/flow_keys.h> #include <xen/xen.h> #include <xen/events.h> @@ -1352,6 +1353,7 @@ static int checksum_setup(struct xenvif if (th >= skb_tail_pointer(skb)) goto out; + skb_set_transport_header(skb, 4 * iph->ihl); skb->csum_start = th - skb->head; switch (iph->protocol) { case IPPROTO_TCP: @@ -1665,6 +1667,7 @@ static void xen_netbk_tx_submit(struct x skb->dev = vif->dev; skb->protocol = eth_type_trans(skb, skb->dev); + skb_reset_network_header(skb); if (checksum_setup(vif, skb)) { netdev_dbg(vif->dev, @@ -1673,6 +1676,15 @@ static void xen_netbk_tx_submit(struct x continue; } + if (!skb_transport_header_was_set(skb)) { + struct flow_keys keys; + + if (skb_flow_dissect(skb, &keys)) + skb_set_transport_header(skb, keys.thoff); + else + skb_reset_transport_header(skb); + } + vif->dev->stats.rx_bytes += skb->len; vif->dev->stats.rx_packets++; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html