Messages in this thread | | | Date | Thu, 11 Apr 2013 14:37:02 +0800 | From | Jason Wang <> | Subject | Re: [net-next 4/5] netback: set transport header before passing it to kernel |
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On 04/10/2013 09:33 PM, Ian Campbell wrote: > 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?
Yes, and furthermore looks like we can use skb_partial_csum_set() here, will send a patch.
Thanks >> 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++; >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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