Subject: Re: [RFC][PATCH 2/9] deadlock prevention core
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Thomas Graf <tgraf@suug.ch>
Cc: Daniel Phillips <phillips@google.com>, David Miller <davem@davemloft.net>,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org,
       netdev@vger.kernel.org
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Date: Wed, 09 Aug 2006 18:19:54 +0200
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On Wed, 2006-08-09 at 18:18 +0200, Thomas Graf wrote:
> * Peter Zijlstra <a.p.zijlstra@chello.nl> 2006-08-09 16:07
> > I think Daniel was thinking of adding struct net_device *
> > sk_buff::alloc_dev,
> > I know I was after reading the first few mails. However if adding a
> > field 
> > there is strict no-no....
> > 
> > /me takes a look at struct sk_buff
> > 
> > Hmm, what does sk_buff::input_dev do? That seems to store the initial
> > device?
> 
> No, skb->input_dev is used when redirecting packets around in the
> stack and may change. Even if it would keep its value the reference
> to the netdevice is not valid anymore when you free the skb as the
> skb was queued and the refcnt acquired in __netifx_rx_schedule()
> has been released again thus making it possible for the netdevice
> to disappear.

Bah, tricky stuff that.

disregards this part from -v2 then :-(


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