Re: [Xen-devel] [PATCH net-next] xen-netfront: add support for IPv6 offloads

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 15/01/14 15:18, Paul Durrant wrote:
> This patch adds support for IPv6 checksum offload and GSO when those
> features are available in the backend.
>
> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> ---
>  drivers/net/xen-netfront.c |   48 
> +++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 43 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
> index c41537b..321759f 100644
> --- a/drivers/net/xen-netfront.c
> +++ b/drivers/net/xen-netfront.c
> @@ -617,7 +617,9 @@ static int xennet_start_xmit(struct sk_buff *skb, struct 
> net_device *dev)
>               tx->flags |= XEN_NETTXF_extra_info;
>  
>               gso->u.gso.size = skb_shinfo(skb)->gso_size;
> -             gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
> +             gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
> +                     XEN_NETIF_GSO_TYPE_TCPV6 :
> +                     XEN_NETIF_GSO_TYPE_TCPV4;
>               gso->u.gso.pad = 0;
>               gso->u.gso.features = 0;
>  
> @@ -809,15 +811,18 @@ static int xennet_set_skb_gso(struct sk_buff *skb,
>               return -EINVAL;
>       }
>  
> -     /* Currently only TCPv4 S.O. is supported. */
> -     if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
> +     if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
> +         gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
>               if (net_ratelimit())
>                       pr_warn("Bad GSO type %d\n", gso->u.gso.type);
>               return -EINVAL;
>       }
>  
>       skb_shinfo(skb)->gso_size = gso->u.gso.size;
> -     skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
> +     skb_shinfo(skb)->gso_type =
> +             (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
> +             SKB_GSO_TCPV4 :
> +             SKB_GSO_TCPV6;
>  
>       /* Header must be checked, and gso_segs computed. */
>       skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
> @@ -1191,6 +1196,15 @@ static netdev_features_t xennet_fix_features(struct 
> net_device *dev,
>                       features &= ~NETIF_F_SG;
>       }
>  
> +     if (features & NETIF_F_IPV6_CSUM) {
> +             if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
> +                              "feature-ipv6-csum-offload", "%d", &val) < 0)
> +                     val = 0;
> +
> +             if (!val)
> +                     features &= ~NETIF_F_IPV6_CSUM;
> +     }
> +
>       if (features & NETIF_F_TSO) {
>               if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
>                                "feature-gso-tcpv4", "%d", &val) < 0)
> @@ -1200,6 +1214,15 @@ static netdev_features_t xennet_fix_features(struct 
> net_device *dev,
>                       features &= ~NETIF_F_TSO;
>       }
>  
> +     if (features & NETIF_F_TSO6) {
> +             if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
> +                              "feature-gso-tcpv6", "%d", &val) < 0)
> +                     val = 0;
> +
> +             if (!val)
> +                     features &= ~NETIF_F_TSO6;
> +     }
> +
>       return features;
>  }
>  
> @@ -1338,7 +1361,9 @@ static struct net_device *xennet_create_dev(struct 
> xenbus_device *dev)
>       netif_napi_add(netdev, &np->napi, xennet_poll, 64);
>       netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
>                                 NETIF_F_GSO_ROBUST;
> -     netdev->hw_features     = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO;
> +     netdev->hw_features     = NETIF_F_SG |
> +                               NETIF_F_IPV6_CSUM |
> +                               NETIF_F_TSO | NETIF_F_TSO6;
>  
>       /*
>           * Assume that all hw features are available for now. This set
> @@ -1716,6 +1741,19 @@ again:
>               goto abort_transaction;
>       }
>  
> +     err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv6", "%d", 1);

"%d", 1 results in a constant string.  xenbus_write() would avoid a
transitory memory allocation.

~Andrew

> +     if (err) {
> +             message = "writing feature-gso-tcpv6";
> +             goto abort_transaction;
> +     }
> +
> +     err = xenbus_printf(xbt, dev->nodename, "feature-ipv6-csum-offload",
> +                         "%d", 1);
> +     if (err) {
> +             message = "writing feature-ipv6-csum-offload";
> +             goto abort_transaction;
> +     }
> +
>       err = xenbus_transaction_end(xbt, 0);
>       if (err) {
>               if (err == -EAGAIN)


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