Subject: Re: [PATCH net-next V2] virtio-net: synchronize operstate with admin state on up/down

From: "Michael S. Tsirkin" <[email-masked]>
Date: Thu, 30 May 2024 02:10:02 -0400

On Thu, May 30, 2024 at 11:20:55AM +0800, Jason Wang wrote:
> This patch synchronize operstate with admin state per RFC2863.
> 
> This is done by trying to toggle the carrier upon open/close and
> synchronize with the config change work. This allows propagate status
> correctly to stacked devices like:
> 
> ip link add link enp0s3 macvlan0 type macvlan
> ip link set link enp0s3 down
> ip link show
> 
> Before this patch:
> 
> 3: enp0s3: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
>     link/ether 00:00:05:00:00:09 brd ff:ff:ff:ff:ff:ff
> ......
> 5: macvlan0@enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
>     link/ether b2:a9:c5:04:da:53 brd ff:ff:ff:ff:ff:ff
> 
> After this patch:
> 
> 3: enp0s3: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
>     link/ether 00:00:05:00:00:09 brd ff:ff:ff:ff:ff:ff
> ...
> 5: macvlan0@enp0s3: <NO-CARRIER,BROADCAST,MULTICAST,UP,M-DOWN> mtu 1500 qdisc noqueue state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
>     link/ether b2:a9:c5:04:da:53 brd ff:ff:ff:ff:ff:ff
> 
> Cc: Venkat Venkatsubra <[email-masked]>
> Cc: Gia-Khanh Nguyen <[email-masked]>
> Reviewed-by: Xuan Zhuo <[email-masked]>
> Acked-by: Michael S. Tsirkin <[email-masked]>
> Signed-off-by: Jason Wang <[email-masked]>
> ---
> Changes since V1:
> - rebase
> - add ack/review tags

> ---
>  drivers/net/virtio_net.c | 94 +++++++++++++++++++++++++++-------------
>  1 file changed, 63 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 4a802c0ea2cb..69e4ae353c51 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -433,6 +433,12 @@ struct virtnet_info {
>  	/* The lock to synchronize the access to refill_enabled */
>  	spinlock_t refill_lock;
>  
> +	/* Is config change enabled? */
> +	bool config_change_enabled;
> +
> +	/* The lock to synchronize the access to config_change_enabled */
> +	spinlock_t config_change_lock;
> +
>  	/* Work struct for config space updates */
>  	struct work_struct config_work;
>  

But we already have dev->config_lock and dev->config_enabled.

And it actually works better - instead of discarding config
change events it defers them until enabled.

> @@ -623,6 +629,20 @@ static void disable_delayed_refill(struct virtnet_info *vi)
>  	spin_unlock_bh(&vi->refill_lock);
>  }
>  
> +static void enable_config_change(struct virtnet_info *vi)
> +{
> +	spin_lock_irq(&vi->config_change_lock);
> +	vi->config_change_enabled = true;
> +	spin_unlock_irq(&vi->config_change_lock);
> +}
> +
> +static void disable_config_change(struct virtnet_info *vi)
> +{
> +	spin_lock_irq(&vi->config_change_lock);
> +	vi->config_change_enabled = false;
> +	spin_unlock_irq(&vi->config_change_lock);
> +}
> +
>  static void enable_rx_mode_work(struct virtnet_info *vi)
>  {
>  	rtnl_lock();
> @@ -2421,6 +2441,25 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
>  	return err;
>  }
>  
> +static void virtnet_update_settings(struct virtnet_info *vi)
> +{
> +	u32 speed;
> +	u8 duplex;
> +
> +	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX))
> +		return;
> +
> +	virtio_cread_le(vi->vdev, struct virtio_net_config, speed, &speed);
> +
> +	if (ethtool_validate_speed(speed))
> +		vi->speed = speed;
> +
> +	virtio_cread_le(vi->vdev, struct virtio_net_config, duplex, &duplex);
> +
> +	if (ethtool_validate_duplex(duplex))
> +		vi->duplex = duplex;
> +}
> +
>  static int virtnet_open(struct net_device *dev)
>  {
>  	struct virtnet_info *vi = netdev_priv(dev);
> @@ -2439,6 +2478,18 @@ static int virtnet_open(struct net_device *dev)
>  			goto err_enable_qp;
>  	}
>  
> +	/* Assume link up if device can't report link status,
> +	   otherwise get link status from config. */
> +	netif_carrier_off(dev);
> +	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> +		enable_config_change(vi);
> +		schedule_work(&vi->config_work);
> +	} else {
> +		vi->status = VIRTIO_NET_S_LINK_UP;
> +		virtnet_update_settings(vi);
> +		netif_carrier_on(dev);
> +	}
> +
>  	return 0;
>  
>  err_enable_qp:
> @@ -2875,12 +2926,19 @@ static int virtnet_close(struct net_device *dev)
>  	disable_delayed_refill(vi);
>  	/* Make sure refill_work doesn't re-enable napi! */
>  	cancel_delayed_work_sync(&vi->refill);
> +	/* Make sure config notification doesn't schedule config work */
> +	disable_config_change(vi);
> +	/* Make sure status updating is cancelled */
> +	cancel_work_sync(&vi->config_work);
>  
>  	for (i = 0; i < vi->max_queue_pairs; i++) {
>  		virtnet_disable_queue_pair(vi, i);
>  		cancel_work_sync(&vi->rq[i].dim.work);
>  	}
>  
> +	vi->status &= ~VIRTIO_NET_S_LINK_UP;
> +	netif_carrier_off(dev);
> +
>  	return 0;
>  }
>  
> @@ -4583,25 +4641,6 @@ static void virtnet_init_settings(struct net_device *dev)
>  	vi->duplex = DUPLEX_UNKNOWN;
>  }
>  
> -static void virtnet_update_settings(struct virtnet_info *vi)
> -{
> -	u32 speed;
> -	u8 duplex;
> -
> -	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX))
> -		return;
> -
> -	virtio_cread_le(vi->vdev, struct virtio_net_config, speed, &speed);
> -
> -	if (ethtool_validate_speed(speed))
> -		vi->speed = speed;
> -
> -	virtio_cread_le(vi->vdev, struct virtio_net_config, duplex, &duplex);
> -
> -	if (ethtool_validate_duplex(duplex))
> -		vi->duplex = duplex;
> -}
> -
>  static u32 virtnet_get_rxfh_key_size(struct net_device *dev)
>  {
>  	return ((struct virtnet_info *)netdev_priv(dev))->rss_key_size;
> @@ -5163,7 +5202,10 @@ static void virtnet_config_changed(struct virtio_device *vdev)
>  {
>  	struct virtnet_info *vi = vdev->priv;
>  
> -	schedule_work(&vi->config_work);
> +	spin_lock_irq(&vi->config_change_lock);
> +	if (vi->config_change_enabled)
> +		schedule_work(&vi->config_work);
> +	spin_unlock_irq(&vi->config_change_lock);
>  }
>  
>  static void virtnet_free_queues(struct virtnet_info *vi)
> @@ -5706,6 +5748,7 @@ static int virtnet_probe(struct virtio_device *vdev)
>  	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
>  	INIT_WORK(&vi->rx_mode_work, virtnet_rx_mode_work);
>  	spin_lock_init(&vi->refill_lock);
> +	spin_lock_init(&vi->config_change_lock);
>  
>  	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) {
>  		vi->mergeable_rx_bufs = true;
> @@ -5901,17 +5944,6 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		goto free_unregister_netdev;
>  	}
>  
> -	/* Assume link up if device can't report link status,
> -	   otherwise get link status from config. */
> -	netif_carrier_off(dev);
> -	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
> -		schedule_work(&vi->config_work);
> -	} else {
> -		vi->status = VIRTIO_NET_S_LINK_UP;
> -		virtnet_update_settings(vi);
> -		netif_carrier_on(dev);
> -	}
> -
>  	for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
>  		if (virtio_has_feature(vi->vdev, guest_offloads[i]))
>  			set_bit(guest_offloads[i], &vi->guest_offloads);
> -- 
> 2.42.0