Re: [PATCH net-next 4/4] udp: Support UDP fraglist GRO/GSO.

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

On Wed, Dec 18, 2019 at 8:35 AM Steffen Klassert
<steffen.klassert@secunet.com> wrote:
>
> This patch extends UDP GRO to support fraglist GRO/GSO
> by using the previously introduced infrastructure.
> If the feature is enabled, all UDP packets are going to
> fraglist GRO (local input and forward).
>
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

> -INDIRECT_CALLABLE_DECLARE(struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
> -                                                  __be16 sport, __be16 dport));
>  struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
> -                               struct udphdr *uh, udp_lookup_t lookup)
> +                               struct udphdr *uh, struct sock *sk)
>  {
>         struct sk_buff *pp = NULL;
>         struct sk_buff *p;
>         struct udphdr *uh2;
>         unsigned int off = skb_gro_offset(skb);
>         int flush = 1;
> -       struct sock *sk;
>
> -       rcu_read_lock();
> -       sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
> -                               udp4_lib_lookup_skb, skb, uh->source, uh->dest);
> -       if (!sk)
> -               goto out_unlock;
> +       if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
> +               NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1;
>
> -       if (udp_sk(sk)->gro_enabled) {
> +       if ((sk && udp_sk(sk)->gro_enabled) ||  NAPI_GRO_CB(skb)->is_flist) {

nit: two spaces before NAPI_GRO_CB

> @@ -544,6 +585,18 @@ INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
>         const struct iphdr *iph = ip_hdr(skb);
>         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
>
> +       if (NAPI_GRO_CB(skb)->is_flist) {
> +               uh->len = htons(skb->len - nhoff);
> +
> +               skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
> +               skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
> +
> +               skb->ip_summed = CHECKSUM_UNNECESSARY;
> +               skb->csum_level = ~0;

why is this needed for ipv4 only?


> @@ -144,6 +150,15 @@ INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff)
>         const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
>         struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
>
> +       if (NAPI_GRO_CB(skb)->is_flist) {
> +               uh->len = htons(skb->len - nhoff);
> +
> +               skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
> +               skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
> +
> +               return 0;
> +       }