Subject: Re: [PATCH 06/10] s390: use RCU to walk list of network devices

From: Eric Dumazet <[email-masked]>
Date: Tue, 10 Nov 2009 19:27:11 +0100

Stephen Hemminger a écrit :
> This is similar to other cases where for_each_netdev_rcu
> can be used when gathering information.
> 
> By inspection, don't have platform or cross-build environment
> to validate.
> 
> Signed-off-by: Stephen Hemminger <[email-masked]>
> 
> 
> --- a/arch/s390/appldata/appldata_net_sum.c	2009-11-09 22:19:05.593480476 -0800
> +++ b/arch/s390/appldata/appldata_net_sum.c	2009-11-10 09:28:38.335438652 -0800
> @@ -83,8 +83,9 @@ static void appldata_get_net_sum_data(vo
>  	rx_dropped = 0;
>  	tx_dropped = 0;
>  	collisions = 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 = dev_get_stats(dev);
>  
>  		rx_packets += stats->rx_packets;
> @@ -98,7 +99,8 @@ static void appldata_get_net_sum_data(vo
>  		collisions += stats->collisions;
>  		i++;
>  	}
> -	read_unlock(&dev_base_lock);
> +	rcu_read_unlock();
> +
>  	net_data->nr_interfaces = i;
>  	net_data->rx_packets = rx_packets;
>  	net_data->tx_packets = tx_packets;
> 

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