Re: [ 12/53] net: In unregister_netdevice_notifier unregister thenetdevices.

[Herton Ronaldo Krzesinski]

On Fri, May 18, 2012 at 03:33:06AM +0100, Ben Hutchings wrote:
> 3.2.18-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> 
> [ Upstream commit 7d3d43dab4e978d8d9ad1acf8af15c9b1c4b0f0f ]
> 
> We already synthesize events in register_netdevice_notifier and synthesizing
> events in unregister_netdevice_notifier allows to us remove the need for
> special case cleanup code.
> 
> This change should be safe as it adds no new cases for existing callers
> of unregiser_netdevice_notifier to handle.

It seems this introduces a regression later fixed by commit
c57b54684060c8aced64a5b78ff69ff289af97b9

> 
> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> ---
>  net/core/dev.c |   20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 55cd370..d1d2a56 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -1421,14 +1421,34 @@ EXPORT_SYMBOL(register_netdevice_notifier);
>   *	register_netdevice_notifier(). The notifier is unlinked into the
>   *	kernel structures and may then be reused. A negative errno code
>   *	is returned on a failure.
> + *
> + * 	After unregistering unregister and down device events are synthesized
> + *	for all devices on the device list to the removed notifier to remove
> + *	the need for special case cleanup code.
>   */
>  
>  int unregister_netdevice_notifier(struct notifier_block *nb)
>  {
> +	struct net_device *dev;
> +	struct net *net;
>  	int err;
>  
>  	rtnl_lock();
>  	err = raw_notifier_chain_unregister(&netdev_chain, nb);
> +	if (err)
> +		goto unlock;
> +
> +	for_each_net(net) {
> +		for_each_netdev(net, dev) {
> +			if (dev->flags & IFF_UP) {
> +				nb->notifier_call(nb, NETDEV_GOING_DOWN, dev);
> +				nb->notifier_call(nb, NETDEV_DOWN, dev);
> +			}
> +			nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
> +			nb->notifier_call(nb, NETDEV_UNREGISTER_BATCH, dev);
> +		}
> +	}
> +unlock:
>  	rtnl_unlock();
>  	return err;
>  }
> -- 
> 1.7.10.1
> 
> 
> 
> 
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-- 
[]'s
Herton
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