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Date: Wed, 12 Mar 2003 02:03:14 +0100 (CET)
From: Roman Zippel <zippel@linux-m68k.org>
X-X-Sender: roman@serv
To: Stephen Hemminger <shemminger@osdl.org>
cc: Linus Torvalds <torvalds@transmeta.com>, David Miller <davem@redhat.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       <linux-net@vger.kernel.org>
Subject: Re: [PATCH] (1/8) Eliminate brlock in psnap
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 <1047428075.15875.97.camel@dell_ss3.pdx.osdl.net>
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Hi,

On 11 Mar 2003, Stephen Hemminger wrote:

>  void unregister_snap_client(struct datalink_proto *proto)
>  {
> -	br_write_lock_bh(BR_NETPROTO_LOCK);
> +	static RCU_HEAD(snap_rcu);
>  
> -	list_del(&proto->node);
> -	kfree(proto);
> +	spin_lock_bh(&snap_lock);
> +	list_del_rcu(&proto->node);
> +	spin_unlock_bh(&snap_lock);
>  
> -	br_write_unlock_bh(BR_NETPROTO_LOCK);
> +	call_rcu(&snap_rcu, (void (*)(void *)) kfree, proto);
>  }

Is this really correct? What happens with snap_rcu, if 
unregister_snap_client is called again, before the call_rcu callback 
finished?

bye, Roman

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