Subject: Re: [PATCH] IPoIB: Stop lying about hard_header_len and use skb->cb to stash LL addresses

From: Or Gerlitz <[email-masked]>
Date: Wed, 8 Feb 2012 16:28:47 +0200

On 2/8/2012 9:50 AM, Eric Dumazet wrote:
> Le mercredi 08 février 2012 à 07:29 +0000, Hefty, Sean a écrit :
>> I tested this with Dave's patch and Eric's first patch against Linus' latest tree 3.3-rc2+, and things look good so far.
>>
>
> Thanks for testing, I'll resend my (updated) patch today.

same here, I used Roland's patch on top of net-next plus the below patch 
and got GRO to aggregate okay,
great doing! Eric, could you please post your work to Dave after 
Roland's patch is applied?

Or.

> diff --git a/net/core/dev.c b/net/core/dev.c
> index f124947..9b8e2fa 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -3491,14 +3491,20 @@ static inline gro_result_t
>  __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
>  {
>         struct sk_buff *p;
> +       unsigned int maclen = skb->dev->hard_header_len;
>
>         for (p = napi->gro_list; p; p = p->next) {
>                 unsigned long diffs;
>
>                 diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
>                 diffs |= p->vlan_tci ^ skb->vlan_tci;
> -               diffs |= compare_ether_header(skb_mac_header(p),
> -                                             skb_gro_mac_header(skb));
> +               if (maclen == ETH_HLEN)
> +                       diffs |= compare_ether_header(skb_mac_header(p),
> +                                                     
> skb_gro_mac_header(skb));
> +               else if (!diffs)
> +                       diffs = memcmp(skb_mac_header(p),
> +                                       skb_gro_mac_header(skb),
> +                                       maclen);
>                 NAPI_GRO_CB(p)->same_flow = !diffs;
>                 NAPI_GRO_CB(p)->flush = 0;
>         }