Subject: Re: [1/3] IRDA: Create new field tx_extra in skbuff

From: Samuel Ortiz <[email-masked]>
Date: Tue, 11 Nov 2008 02:00:01 +0100

On Mon, Nov 10, 2008 at 07:55:44PM +0300, Evgeniy Polyakov wrote:
> On Mon, Nov 10, 2008 at 07:35:46PM +0300, Evgeniy Polyakov ([email-masked]) wrote:
> > What exactly should be carried in that area?
> 
> It is struct irda_skb_cb, which contains qos and other bits of
> intormation about how to transfer data, which are in turn obtained from
> various _cb IRDA structures, which I tracked upto to for example
> lsap_cb, which exists in the hash table. Do others also accessible via
> similar mechanism? Can that data be stored on per-device basis like
> ethernet checksum/offloading parameters (for example like LRO is done)?
I thought about that solution, but the irda_skb_cb line field has to be kept
per skb. It is needed for ircomm LMP flow control, in the skb destructor. I
see that BT rfcomm does something similar, but uses the skbuff->sk as a
rfcomm_dev pointer. As far as I understand the skbuff structure, that doesnt
look like a reasonnable solution, as we cant assume the sk pointer won't be
altered down the line.

Cheers,
Samuel.

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