From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next 3/9] IB/ipoib: Add support for acting as VIF
Date: Wed, 11 Jul 2012 01:19:12 -0700 (PDT)
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From: Or Gerlitz <ogerlitz@mellanox.com>
Date: Wed, 11 Jul 2012 11:05:12 +0300

> On 7/10/2012 3:26 PM, Eric Dumazet wrote:
>> On Tue, 2012-07-10 at 15:16 +0300, Or Gerlitz wrote:
>>> The IPoIB code checks the VIF private flag on the RX path, and
>>> accoriding
>>> to the value of the flag prepares the skb CB data, etc.
>>>
>>
>> skb->cb[] can be destroyed in netif_receive_skb() /
>> __netif_receive_skb()
>>
>> #ifdef CONFIG_NET_CLS_ACT
>> 	skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
>> 	...
>> #endif
> 
> Eric,
> 
> Can you elaborate a little further? we're not sure to see where
> skb->cb[] is touched on the flow
> you pointed to.

handle_ing() goes into the packet scheduler and qdisc layer,
the qdisc layer uses skb->cb[] via struct qdisc_skb_cb.