From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: Re-queueing of skb in vlan_skb_recv
Date: Fri, 11 Apr 2008 13:53:13 +0100
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Cc: Brian Oostenbrink <Brian_Oostenbrink@pmc-sierra.com>,
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	Linux Netdev List <netdev@vger.kernel.org>
To: Patrick McHardy <kaber@trash.net>
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On Fri, Apr 11, 2008 at 02:46:35PM +0200, Patrick McHardy wrote:
> Brian Oostenbrink wrote:
> >In vlan_skb_recv, packets are generally stripped of their vlan header,
> >and then re-queued via netif_rx().  Is there a reason for re-queuing
> >these instead of calling netif_receive_skb() directly?  On our system
> >(an embedded linux router), this re-queuing has a significant
> >performance penalty.
> 
> Its done to save stack space. There's currently a discussion
> about making loopback use netif_receive_skb in case enough
> stack is still available. Once that patch gets merged I'll
> change VLAN in a similar way.

Another possibility would be to allow ->func() of packet_type to return an
skb for reprocessing...