Re: [PATCH net-next] net: core: Expose number of link up/down transitions

[David Ahern]

On 1/17/18 3:06 PM, Florian Fainelli wrote:
> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
> index 7bf8b85ade16..9f732c3dc2ce 100644
> --- a/net/core/net-sysfs.c
> +++ b/net/core/net-sysfs.c
> @@ -295,10 +295,29 @@ static ssize_t carrier_changes_show(struct device *dev,
>  	struct net_device *netdev = to_net_dev(dev);
>  
>  	return sprintf(buf, fmt_dec,
> -		       atomic_read(&netdev->carrier_changes));
> +		       atomic_read(&netdev->count_link_up) +
> +		       atomic_read(&netdev->count_link_down));
>  }
>  static DEVICE_ATTR_RO(carrier_changes);
>  
> +static ssize_t count_link_up_show(struct device *dev,
> +				  struct device_attribute *attr, char *buf)
> +{
> +	struct net_device *netdev = to_net_dev(dev);
> +
> +	return sprintf(buf, fmt_dec, atomic_read(&netdev->count_link_up));
> +}
> +static DEVICE_ATTR_RO(count_link_up);
> +
> +static ssize_t count_link_down_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	struct net_device *netdev = to_net_dev(dev);
> +
> +	return sprintf(buf, fmt_dec, atomic_read(&netdev->count_link_down));
> +}
> +static DEVICE_ATTR_RO(count_link_down);
> +
>  /* read-write attributes */
>  
>  static int change_mtu(struct net_device *dev, unsigned long new_mtu)
> @@ -547,6 +566,8 @@ static struct attribute *net_class_attrs[] __ro_after_init = {
>  	&dev_attr_phys_port_name.attr,
>  	&dev_attr_phys_switch_id.attr,
>  	&dev_attr_proto_down.attr,
> +	&dev_attr_count_link_up.attr,
> +	&dev_attr_count_link_down.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(net_class);

Personally, I do not like adding any more sysfs files. As discussed in
the past sysfs is a huge contributor to the overhead of netdevs.