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From: David Miller <davem@davemloft.net>
To: steffen.klassert@secunet.com
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org
Subject: Re: [PATCH 1/2] xfrm: Force a dst refcount before entering the xfrm type handlers
Date: Wed, 16 Mar 2011 10:41:18 -0700 (PDT)	[thread overview]
Message-ID: <20110316.104118.71120514.davem@davemloft.net> (raw)
In-Reply-To: <20110316074306.GT31402@secunet.com>

From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Wed, 16 Mar 2011 08:43:06 +0100

> On Wed, Mar 16, 2011 at 12:17:32AM -0700, David Miller wrote:
>> 
>> Steffen we really need to find another way to fix these problems.
>> 
>> We already make way too many expensive atomic operations in these code
>> paths modified by your 3 patches, we should strive to not add new
>> ones.
>> 
> 
> I know that it is exspensive, but we have to take a refcount if
> the crypto layer returns asyncronous. Unfortunately it is too
> late to take the refcount when the crypto layer notifies us about
> that as the skb might be already gone.

We can pass around an atomic_t for the crypto layer to bump when
it decides to take an async path, bump it on entry and upon event
wakeup decrement it.

Actually, a plain atomic_t is a bad idea because we might have to
release the object.  So callbacks with private void pointer arg is
better.

      reply	other threads:[~2011-03-16 17:40 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-16  7:08 [PATCH 1/2] xfrm: Force a dst refcount before entering the xfrm type handlers Steffen Klassert
2011-03-16  7:09 ` [PATCH 2/2] dst: Clone child entry in skb_dst_pop Steffen Klassert
2011-03-16  7:17 ` [PATCH 1/2] xfrm: Force a dst refcount before entering the xfrm type handlers David Miller
2011-03-16  7:43   ` Steffen Klassert
2011-03-16 17:41     ` David Miller [this message]

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