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

[Jason Wang <jasowang@redhat.com>]

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 <venkat.x.venkatsubra@oracle.com>
Cc: Gia-Khanh Nguyen <gia-khanh.nguyen@oracle.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
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;
 
@@ -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