Messages in this thread Patch in this message | | | Subject | Re: [net-next 4/5] netback: set transport header before passing it to kernel | From | Ian Campbell <> | Date | Wed, 10 Apr 2013 14:33:23 +0100 |
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On Tue, 2013-03-26 at 06:19 +0000, Jason Wang wrote: > 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. > > Cc: Eric Dumazet <edumazet@google.com> > Cc: Ian Campbell <ian.campbell@citrix.com> > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > drivers/net/xen-netback/netback.c | 12 ++++++++++++ > 1 files changed, 12 insertions(+), 0 deletions(-) > > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index aa28550..fc8faa7 100644 > --- 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> > @@ -1184,6 +1185,7 @@ static int checksum_setup(struct xenvif *vif, struct sk_buff *skb) > if (th >= skb_tail_pointer(skb)) > goto out; > > + skb_set_transport_header(skb, 4 * iph->ihl); > skb->csum_start = th - skb->head;
Should the use of th here (and perhaps above) be replaced with skb_transport_header() too?
> switch (iph->protocol) { > case IPPROTO_TCP: > @@ -1495,6 +1497,7 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk) > > 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, > @@ -1503,6 +1506,15 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk) > 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++; >
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