From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH 06/10] s390: use RCU to walk list of network devices
Date: Tue, 10 Nov 2009 19:27:11 +0100
Message-ID: <4AF9B07F.6070606@gmail.com>
References: <20091110175446.280423729@vyatta.com> <20091110175647.547660685@vyatta.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: QUOTED-PRINTABLE
Cc: David Miller <davem@davemloft.net>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	netdev@vger.kernel.org, linux390@de.ibm.com
To: Stephen Hemminger <shemminger@vyatta.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from gw1.cosmosbay.com ([212.99.114.194]:37528 "EHLO
	gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1752170AbZKJS1J (ORCPT
	<rfc822;netdev@vger.kernel.org>); Tue, 10 Nov 2009 13:27:09 -0500
In-Reply-To: <20091110175647.547660685@vyatta.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

Stephen Hemminger a =E9crit :
> This is similar to other cases where for_each_netdev_rcu
> can be used when gathering information.
>=20
> By inspection, don't have platform or cross-build environment
> to validate.
>=20
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>=20
>=20
> --- a/arch/s390/appldata/appldata_net_sum.c	2009-11-09 22:19:05.59348=
0476 -0800
> +++ b/arch/s390/appldata/appldata_net_sum.c	2009-11-10 09:28:38.33543=
8652 -0800
> @@ -83,8 +83,9 @@ static void appldata_get_net_sum_data(vo
>  	rx_dropped =3D 0;
>  	tx_dropped =3D 0;
>  	collisions =3D 0;
> -	read_lock(&dev_base_lock);
> -	for_each_netdev(&init_net, dev) {
> +
> +	rcu_read_lock();
> +	for_each_netdev_rcu(&init_net, dev) {
>  		const struct net_device_stats *stats =3D dev_get_stats(dev);
> =20
>  		rx_packets +=3D stats->rx_packets;
> @@ -98,7 +99,8 @@ static void appldata_get_net_sum_data(vo
>  		collisions +=3D stats->collisions;
>  		i++;
>  	}
> -	read_unlock(&dev_base_lock);
> +	rcu_read_unlock();
> +
>  	net_data->nr_interfaces =3D i;
>  	net_data->rx_packets =3D rx_packets;
>  	net_data->tx_packets =3D tx_packets;
>=20

Not sure if dev_get_stats(dev) could sleep on some devices...