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Date: Tue, 04 Apr 2006 17:07:20 -0700 (PDT)
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To: gregkh@suse.de
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Subject: Re: [patch 11/26] IPOB: Move destructor from neigh->ops to
 neigh_param
From: "David S. Miller" <davem@davemloft.net>
In-Reply-To: <20060405000030.GL27049@kroah.com>
References: <20060404235634.696852000@quad.kroah.org>
	<20060404235927.GA27049@kroah.com>
	<20060405000030.GL27049@kroah.com>
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From: gregkh@suse.de
Date: Tue, 4 Apr 2006 17:00:30 -0700

> From: Michael Tsirkin <mst@mellanox.co.il>
> 
> struct neigh_ops currently has a destructor field, but not a constructor field.
> The infiniband/ulp/ipoib in-tree driver stashes some info in the neighbour
> structure (the results of the second-stage lookup from ARP results to real
> link-level path), and it uses neigh->ops->destructor to get a callback so it can
> clean up this extra info when a neighbour is freed.  We've run into problems
> with this: since the destructor is in an ops field that is shared between
> neighbours that may belong to different net devices, there's no way to set/clear
> it safely.
> 
> The following patch moves this field to neigh_parms where it can be safely set,
> together with its twin neigh_setup, and switches the only two in-kernel users
> (ipoib and clip) to this interface.

Major NAK.

This does not fix a bug, it is merely and API change that the
inifiniband folks want for some of their infrastructure.

It was accepted for 2.6.17, but this change is not appropriate
for the -stable release branch.

Furthermore, this version of the patch here will break the build of
ATM.