Subject: Re: [PATCH net,v3] hyperv: Fix the carrier status setting

From: Jason Wang <[email-masked]>
Date: Thu, 13 Feb 2014 11:51:35 +0800

On 02/13/2014 08:54 AM, Haiyang Zhang wrote:
> Without this patch, the "cat /sys/class/net/ethN/operstate" shows
> "unknown", and "ethtool ethN" shows "Link detected: yes", when VM
> boots up with or without vNIC connected.
>
> This patch fixed the problem.
>
> Signed-off-by: Haiyang Zhang <[email-masked]>
> Reviewed-by: K. Y. Srinivasan <[email-masked]>
> ---
>  drivers/net/hyperv/netvsc_drv.c |   53 ++++++++++++++++++++++++++++-----------
>  1 files changed, 38 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 7756118..7141a19 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -88,8 +88,12 @@ static int netvsc_open(struct net_device *net)
>  {
>  	struct net_device_context *net_device_ctx = netdev_priv(net);
>  	struct hv_device *device_obj = net_device_ctx->device_ctx;
> +	struct netvsc_device *nvdev;
> +	struct rndis_device *rdev;
>  	int ret = 0;
>  
> +	netif_carrier_off(net);
> +
>  	/* Open up the device */
>  	ret = rndis_filter_open(device_obj);
>  	if (ret != 0) {
> @@ -99,6 +103,11 @@ static int netvsc_open(struct net_device *net)
>  
>  	netif_start_queue(net);
>  
> +	nvdev = hv_get_drvdata(device_obj);
> +	rdev = nvdev->extension;
> +	if (!rdev->link_state)
> +		netif_carrier_on(net);
> +

Maybe you can just schedule the work here and then you can drop the
rtnl_lock in netvsc_link_change() ?
>  	return ret;
>  }
>  
> @@ -229,23 +238,24 @@ void netvsc_linkstatus_callback(struct hv_device *device_obj,
>  	struct net_device *net;
>  	struct net_device_context *ndev_ctx;
>  	struct netvsc_device *net_device;
> +	struct rndis_device *rdev;
>  
>  	net_device = hv_get_drvdata(device_obj);
> +	rdev = net_device->extension;
> +
> +	rdev->link_state = status != 1;
> +
>  	net = net_device->ndev;
>  
> -	if (!net) {
> -		netdev_err(net, "got link status but net device "
> -				"not initialized yet\n");
> +	if (!net || net->reg_state != NETREG_REGISTERED)
>  		return;
> -	}
>  
> +	ndev_ctx = netdev_priv(net);
>  	if (status == 1) {
> -		netif_carrier_on(net);
> -		ndev_ctx = netdev_priv(net);
>  		schedule_delayed_work(&ndev_ctx->dwork, 0);
>  		schedule_delayed_work(&ndev_ctx->dwork, msecs_to_jiffies(20));
>  	} else {
> -		netif_carrier_off(net);
> +		schedule_delayed_work(&ndev_ctx->dwork, 0);
>  	}
>  }
>  
> @@ -388,17 +398,35 @@ static const struct net_device_ops device_ops = {
>   * current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, add
>   * another netif_notify_peers() into a delayed work, otherwise GARP packet
>   * will not be sent after quick migration, and cause network disconnection.
> + * Also, we update the carrier status here.
>   */
> -static void netvsc_send_garp(struct work_struct *w)
> +static void netvsc_link_change(struct work_struct *w)
>  {
>  	struct net_device_context *ndev_ctx;
>  	struct net_device *net;
>  	struct netvsc_device *net_device;
> +	struct rndis_device *rdev;
> +	bool notify;
> +
> +	rtnl_lock();
>  
>  	ndev_ctx = container_of(w, struct net_device_context, dwork.work);
>  	net_device = hv_get_drvdata(ndev_ctx->device_ctx);
> +	rdev = net_device->extension;
>  	net = net_device->ndev;
> -	netdev_notify_peers(net);
> +
> +	if (rdev->link_state) {
> +		netif_carrier_off(net);
> +		notify = false;
> +	} else {
> +		netif_carrier_on(net);
> +		notify = true;
> +	}
> +
> +	rtnl_unlock();
> +
> +	if (notify)
> +		netdev_notify_peers(net);
>  }
>  

Looks like this forces arp_notify here. Is it expected?

Other looks good.
>  
> @@ -414,13 +442,10 @@ static int netvsc_probe(struct hv_device *dev,
>  	if (!net)
>  		return -ENOMEM;
>  
> -	/* Set initial state */
> -	netif_carrier_off(net);
> -
>  	net_device_ctx = netdev_priv(net);
>  	net_device_ctx->device_ctx = dev;
>  	hv_set_drvdata(dev, net);
> -	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_send_garp);
> +	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
>  	INIT_WORK(&net_device_ctx->work, do_set_multicast);
>  
>  	net->netdev_ops = &device_ops;
> @@ -443,8 +468,6 @@ static int netvsc_probe(struct hv_device *dev,
>  	}
>  	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
>  
> -	netif_carrier_on(net);
> -
>  	ret = register_netdev(net);
>  	if (ret != 0) {
>  		pr_err("Unable to register netdev.\n");