Subject: Re: [PATCH 1/3] vlan: Do not support clearing VLAN_FLAG_REORDER_HDR

From: Nicolas de Pesloüan<[email-masked]>
Date: Tue, 24 May 2011 09:19:55 +0200

Le 24/05/2011 07:58, Jiri Pirko a écrit :
<snip>

>>> Btw what's the rationale to move untag to earlier position?
>>
>> Maybe simply because we try to mimic hw-accel, and hw-accel untagging
>> definitely happens before we enter __netif_receive_skb and only
>> happens once.
>>
>> So having software untagging inside the __netif_receive_skb loop looks different.
>
> I understand. But what code prior to current vlan_untag position needs
> to see the skb untagged?

Any protocol handlers (ptype_all or ptype_base) registered on the parent interface may need to see 
the skb untagged, for all the reasons given in this thread. Arguably, doing software untagging 
earlier wouldn't help. :-) We need a strong logic to decide whether and when to untag and/or 
possibly re-tag.

	Nicolas.