From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-2.6.25] [BRIDGE] Remove useless code in
 net/bridge/br_netfilter.c
Date: Tue, 01 Jan 2008 21:20:26 -0800 (PST)
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To: ramirose@gmail.com
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From: "Rami Rosen" <ramirose@gmail.com>
Date: Tue, 1 Jan 2008 12:48:14 +0200

> These following two commands in br_nf_forward_arp() achieve nothing and
> should be removed; the d variable is not used later in this method:
> 
> 	...
> 	struct net_device **d = (struct net_device **)(skb->cb);
> 	...
> 	*d = (struct net_device *)in;
> 	...
> 
> Signed-off-by: Rami Rosen <ramirose@gmail.com>

It's a pointer dereference assignment, this last line has a
side effect, therefore you can't remove it.

The code is equivalent to:

struct skb_bridge_info {
	struct net_device *dev;
};

	struct skb_bridge_info *d;

	d = (struct skb_bridge_info *) skb->cb;

	d->dev = in;

What automated tool showed this as useless to you?

Please correct it's logic so it doesn't mark real side effects like
this as superfluous.

Thanks.