netdev - Re: [PATCH net-next v1] gso: Support partial splitting at the frag

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Message-ID: <20160829120231.GZ3735@gauss.secunet.com>
Date:   Mon, 29 Aug 2016 14:02:31 +0200
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
CC:     Alexander Duyck <alexander.duyck@...il.com>,
        Netdev <netdev@...r.kernel.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        "Alexander Duyck" <alexander.h.duyck@...el.com>
Subject: Re: [PATCH net-next v1] gso: Support partial splitting at the
 frag_list pointer

On Thu, Aug 25, 2016 at 09:17:18AM -0300, Marcelo Ricardo Leitner wrote:
> On Thu, Aug 25, 2016 at 09:31:26AM +0200, Steffen Klassert wrote:
> > 
> > Just to understand what you are doing. You generate MTU sized linear
> > buffers in sctp and then, skb_gro_receive() chains up these buffers
> > at the frag_list pointer. skb_gro_receive() does this because
> > skb_gro_offset is null and skb->head_frag is not set in your case.
> > 
> > At segmentation, you just need to split at the frag_list pointer
> > because you know that the chained buffers fit the MTU, right?
> > 
> 
> Correct. Just note that these buffers fit the MTU, but not necessary
> uses all of it. That is main point in here, variable segmentation size.

Thanks for the info. This is a very interesting concept, maybe I can use
it for IPsec too.