On Thu, 2015-07-02 at 14:04 -0700, Tom Herbert wrote:
> When setting up the first skb in a gro list we ensure that all the
> headers up to skb_gro_offset have been pulled into head. In subsequent
> uses of this skb (e.g. determining same_flow) it is assumed that the
> headers can be accessed in the skb head.
>
> Signed-off-by: Tom Herbert <t...@herbertland.com>
> ---
> net/core/dev.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 6778a99..05e0e37 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -4228,6 +4228,10 @@ static enum gro_result dev_gro_receive(struct
> napi_struct *napi, struct sk_buff
> } else {
> napi->gro_count++;
> }
> +
> + /* Ensure all headers are pulled into head for 1st skb */
> + skb_gro_header_slow(skb, skb_gro_offset(skb), 0);
> +
> NAPI_GRO_CB(skb)->count = 1;
> NAPI_GRO_CB(skb)->age = jiffies;
> NAPI_GRO_CB(skb)->last = skb;
I do not see how we can reach this point without having headers already
pulled.
For example, tcp_gro_receive() has :
off = skb_gro_offset(skb);
hlen = off + sizeof(*th);
th = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
th = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!th))
goto out;
}
So by definition, skb is put in gro_list only if it was fully validated as a GRO
candidate.
Given the complexity of your 2nd patch, I am stopping the review right
now.
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