Re: [2/2] gro: Add page frag support

[David Miller <davem@davemloft.net>]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 2 Jan 2009 15:20:11 +1100

> Here's an updated version with a redundant blank line removed.
> 
> gro: Add page frag support
> 
> This patch allows GRO to merge page frags (skb_shinfo(skb)->frags)
> in one skb, rather than using the less efficient frag_list.
> 
> It also adds a new interface, napi_gro_frags to allow drivers
> to inject page frags directly into the stack without allocating
> an skb.  This is intended to be the GRO equivalent for LRO's
> lro_receive_frags interface.
> 
> The existing GSO interface can already handle page frags with
> or without an appended frag_list so nothing needs to be changed
> there.
> 
> The merging itself is rather simple.  We store any new frag entries
> after the last existing entry, without checking whether the first
> new entry can be merged with the last existing entry.  Making this
> check would actually be easy but since no existing driver can
> produce contiguous frags anyway it would just be mental masturbation.
> 
> If the total number of entries would exceed the capacity of a
> single skb, we simply resort to using frag_list as we do now.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Also applied, thanks Herbert.