Merge branch 'virtio-net-synchronize-op-admin-state'

Jason Wang says:

====================
virtio-net: synchronize op/admin state

This series tries to synchronize the operstate with the admin state
which allows the lower virtio-net to propagate the link status to the
upper devices like macvlan.

This is done by toggling carrier during ndo_open/stop while doing
other necessary serialization about the carrier settings during probe.

While at it, also fix a race between probe and ndo_set_features as we
didn't initalize the guest offload setting under rtnl lock.
====================

Link: https://patch.msgid.link/20240814052228.4654-1-jasowang@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/virtio_net.c

@@ -2885,6 +2885,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
 	net_dim_work_cancel(dim);
 }
 
+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);
@@ -2903,6 +2922,15 @@ static int virtnet_open(struct net_device *dev)
 			goto err_enable_qp;
 	}
 
+	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
+		if (vi->status & VIRTIO_NET_S_LINK_UP)
+			netif_carrier_on(vi->dev);
+		virtio_config_driver_enable(vi->vdev);
+	} else {
+		vi->status = VIRTIO_NET_S_LINK_UP;
+		netif_carrier_on(dev);
+	}
+
 	return 0;
 
 err_enable_qp:
@@ -3381,12 +3409,22 @@ 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);
+	/* Prevent the config change callback from changing carrier
+	 * after close
+	 */
+	virtio_config_driver_disable(vi->vdev);
+	/* Stop getting status/speed updates: we don't care until next
+	 * open
+	 */
+	cancel_work_sync(&vi->config_work);
 
 	for (i = 0; i < vi->max_queue_pairs; i++) {
 		virtnet_disable_queue_pair(vi, i);
 		virtnet_cancel_dim(vi, &vi->rq[i].dim);
 	}
 
+	netif_carrier_off(dev);
+
 	return 0;
 }
 
@@ -5095,25 +5133,6 @@ 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;
@@ -6524,6 +6543,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 		goto free_failover;
 	}
 
+	/* Disable config change notification until ndo_open. */
+	virtio_config_driver_disable(vi->vdev);
+
 	virtio_device_ready(vdev);
 
 	virtnet_set_queues(vi, vi->curr_queue_pairs);
@@ -6573,19 +6595,11 @@ static int virtnet_probe(struct virtio_device *vdev)
 		vi->device_stats_cap = le64_to_cpu(v);
 	}
 
-	rtnl_unlock();
-
-	err = virtnet_cpu_notif_add(vi);
-	if (err) {
-		pr_debug("virtio_net: registering cpu notifier failed\n");
-		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);
+		virtnet_config_changed_work(&vi->config_work);
 	} else {
 		vi->status = VIRTIO_NET_S_LINK_UP;
 		virtnet_update_settings(vi);
@@ -6597,6 +6611,14 @@ static int virtnet_probe(struct virtio_device *vdev)
 			set_bit(guest_offloads[i], &vi->guest_offloads);
 	vi->guest_offloads_capable = vi->guest_offloads;
 
+	rtnl_unlock();
+
+	err = virtnet_cpu_notif_add(vi);
+	if (err) {
+		pr_debug("virtio_net: registering cpu notifier failed\n");
+		goto free_unregister_netdev;
+	}
+
 	pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
 		 dev->name, max_queue_pairs);
 

drivers/virtio/virtio.c

@@ -127,10 +127,12 @@ static void __virtio_config_changed(struct virtio_device *dev)
 {
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 
-	if (!dev->config_enabled)
+	if (!dev->config_core_enabled || dev->config_driver_disabled)
 		dev->config_change_pending = true;
-	else if (drv && drv->config_changed)
+	else if (drv && drv->config_changed) {
 		drv->config_changed(dev);
+		dev->config_change_pending = false;
+	}
 }
 
 void virtio_config_changed(struct virtio_device *dev)
@@ -143,20 +145,51 @@ void virtio_config_changed(struct virtio_device *dev)
 }
 EXPORT_SYMBOL_GPL(virtio_config_changed);
 
-static void virtio_config_disable(struct virtio_device *dev)
+/**
+ * virtio_config_driver_disable - disable config change reporting by drivers
+ * @dev: the device to reset
+ *
+ * This is only allowed to be called by a driver and disabling can't
+ * be nested.
+ */
+void virtio_config_driver_disable(struct virtio_device *dev)
 {
 	spin_lock_irq(&dev->config_lock);
-	dev->config_enabled = false;
+	dev->config_driver_disabled = true;
 	spin_unlock_irq(&dev->config_lock);
 }
+EXPORT_SYMBOL_GPL(virtio_config_driver_disable);
 
-static void virtio_config_enable(struct virtio_device *dev)
+/**
+ * virtio_config_driver_enable - enable config change reporting by drivers
+ * @dev: the device to reset
+ *
+ * This is only allowed to be called by a driver and enabling can't
+ * be nested.
+ */
+void virtio_config_driver_enable(struct virtio_device *dev)
 {
 	spin_lock_irq(&dev->config_lock);
-	dev->config_enabled = true;
+	dev->config_driver_disabled = false;
+	if (dev->config_change_pending)
+		__virtio_config_changed(dev);
+	spin_unlock_irq(&dev->config_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_config_driver_enable);
+
+static void virtio_config_core_disable(struct virtio_device *dev)
+{
+	spin_lock_irq(&dev->config_lock);
+	dev->config_core_enabled = false;
+	spin_unlock_irq(&dev->config_lock);
+}
+
+static void virtio_config_core_enable(struct virtio_device *dev)
+{
+	spin_lock_irq(&dev->config_lock);
+	dev->config_core_enabled = true;
 	if (dev->config_change_pending)
 		__virtio_config_changed(dev);
-	dev->config_change_pending = false;
 	spin_unlock_irq(&dev->config_lock);
 }
 
@@ -316,7 +349,7 @@ static int virtio_dev_probe(struct device *_d)
 	if (drv->scan)
 		drv->scan(dev);
 
-	virtio_config_enable(dev);
+	virtio_config_core_enable(dev);
 
 	return 0;
 
@@ -331,7 +364,7 @@ static void virtio_dev_remove(struct device *_d)
 	struct virtio_device *dev = dev_to_virtio(_d);
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 
-	virtio_config_disable(dev);
+	virtio_config_core_disable(dev);
 
 	drv->remove(dev);
 
@@ -443,7 +476,7 @@ int register_virtio_device(struct virtio_device *dev)
 		goto out_ida_remove;
 
 	spin_lock_init(&dev->config_lock);
-	dev->config_enabled = false;
+	dev->config_core_enabled = false;
 	dev->config_change_pending = false;
 
 	INIT_LIST_HEAD(&dev->vqs);
@@ -500,14 +533,14 @@ int virtio_device_freeze(struct virtio_device *dev)
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 	int ret;
 
-	virtio_config_disable(dev);
+	virtio_config_core_disable(dev);
 
 	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
 
 	if (drv && drv->freeze) {
 		ret = drv->freeze(dev);
 		if (ret) {
-			virtio_config_enable(dev);
+			virtio_config_core_enable(dev);
 			return ret;
 		}
 	}
@@ -557,7 +590,7 @@ int virtio_device_restore(struct virtio_device *dev)
 	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
 		virtio_device_ready(dev);
 
-	virtio_config_enable(dev);
+	virtio_config_core_enable(dev);
 
 	return 0;
 

include/linux/virtio.h

@@ -118,7 +118,9 @@ struct virtio_admin_cmd {
  * struct virtio_device - representation of a device using virtio
  * @index: unique position on the virtio bus
  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
- * @config_enabled: configuration change reporting enabled
+ * @config_core_enabled: configuration change reporting enabled by core
+ * @config_driver_disabled: configuration change reporting disabled by
+ *                          a driver
  * @config_change_pending: configuration change reported while disabled
  * @config_lock: protects configuration change reporting
  * @vqs_list_lock: protects @vqs.
@@ -135,7 +137,8 @@ struct virtio_admin_cmd {
 struct virtio_device {
 	int index;
 	bool failed;
-	bool config_enabled;
+	bool config_core_enabled;
+	bool config_driver_disabled;
 	bool config_change_pending;
 	spinlock_t config_lock;
 	spinlock_t vqs_list_lock;
@@ -166,6 +169,10 @@ void __virtqueue_break(struct virtqueue *_vq);
 void __virtqueue_unbreak(struct virtqueue *_vq);
 
 void virtio_config_changed(struct virtio_device *dev);
+
+void virtio_config_driver_disable(struct virtio_device *dev);
+void virtio_config_driver_enable(struct virtio_device *dev);
+
 #ifdef CONFIG_PM_SLEEP
 int virtio_device_freeze(struct virtio_device *dev);
 int virtio_device_restore(struct virtio_device *dev);