---

yaml
---
r: 300755
b: refs/heads/master
c: 586d17c
h: refs/heads/master
i:
  300753: 094538c
  300751: dba54e4
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8831a3f2c9ee7d952e6d7a018d11c0c9c5b56749
+refs/heads/master: 586d17c5a01bf1ae4e215adc6c48457eee5482bc

trunk/drivers/net/virtio_net.c

@@ -66,12 +66,21 @@ struct virtnet_info {
 	/* Host will merge rx buffers for big packets (shake it! shake it!) */
 	bool mergeable_rx_bufs;
 
+	/* enable config space updates */
+	bool config_enable;
+
 	/* Active statistics */
 	struct virtnet_stats __percpu *stats;
 
 	/* Work struct for refilling if we run low on memory. */
 	struct delayed_work refill;
 
+	/* Work struct for config space updates */
+	struct work_struct config_work;
+
+	/* Lock for config space updates */
+	struct mutex config_lock;
+
 	/* Chain pages by the private ptr. */
 	struct page *pages;
 
@@ -780,6 +789,16 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 	return status == VIRTIO_NET_OK;
 }
 
+static void virtnet_ack_link_announce(struct virtnet_info *vi)
+{
+	rtnl_lock();
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
+				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL,
+				  0, 0))
+		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
+	rtnl_unlock();
+}
+
 static int virtnet_close(struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -951,20 +970,31 @@ static const struct net_device_ops virtnet_netdev = {
 #endif
 };
 
-static void virtnet_update_status(struct virtnet_info *vi)
+static void virtnet_config_changed_work(struct work_struct *work)
 {
+	struct virtnet_info *vi =
+		container_of(work, struct virtnet_info, config_work);
 	u16 v;
 
+	mutex_lock(&vi->config_lock);
+	if (!vi->config_enable)
+		goto done;
+
 	if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
 			      offsetof(struct virtio_net_config, status),
 			      &v) < 0)
-		return;
+		goto done;
+
+	if (v & VIRTIO_NET_S_ANNOUNCE) {
+		netif_notify_peers(vi->dev);
+		virtnet_ack_link_announce(vi);
+	}
 
 	/* Ignore unknown (future) status bits */
 	v &= VIRTIO_NET_S_LINK_UP;
 
 	if (vi->status == v)
-		return;
+		goto done;
 
 	vi->status = v;
 
@@ -975,13 +1005,15 @@ static void virtnet_update_status(struct virtnet_info *vi)
 		netif_carrier_off(vi->dev);
 		netif_stop_queue(vi->dev);
 	}
+done:
+	mutex_unlock(&vi->config_lock);
 }
 
 static void virtnet_config_changed(struct virtio_device *vdev)
 {
 	struct virtnet_info *vi = vdev->priv;
 
-	virtnet_update_status(vi);
+	queue_work(system_nrt_wq, &vi->config_work);
 }
 
 static int init_vqs(struct virtnet_info *vi)
@@ -1075,6 +1107,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 		goto free;
 
 	INIT_DELAYED_WORK(&vi->refill, refill_work);
+	mutex_init(&vi->config_lock);
+	vi->config_enable = true;
+	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
 	sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
 	sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
 
@@ -1110,7 +1145,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 	   otherwise get link status from config. */
 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
 		netif_carrier_off(dev);
-		virtnet_update_status(vi);
+		queue_work(system_nrt_wq, &vi->config_work);
 	} else {
 		vi->status = VIRTIO_NET_S_LINK_UP;
 		netif_carrier_on(dev);
@@ -1169,10 +1204,17 @@ static void __devexit virtnet_remove(struct virtio_device *vdev)
 {
 	struct virtnet_info *vi = vdev->priv;
 
+	/* Prevent config work handler from accessing the device. */
+	mutex_lock(&vi->config_lock);
+	vi->config_enable = false;
+	mutex_unlock(&vi->config_lock);
+
 	unregister_netdev(vi->dev);
 
 	remove_vq_common(vi);
 
+	flush_work(&vi->config_work);
+
 	free_percpu(vi->stats);
 	free_netdev(vi->dev);
 }
@@ -1182,6 +1224,11 @@ static int virtnet_freeze(struct virtio_device *vdev)
 {
 	struct virtnet_info *vi = vdev->priv;
 
+	/* Prevent config work handler from accessing the device */
+	mutex_lock(&vi->config_lock);
+	vi->config_enable = false;
+	mutex_unlock(&vi->config_lock);
+
 	virtqueue_disable_cb(vi->rvq);
 	virtqueue_disable_cb(vi->svq);
 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ))
@@ -1195,6 +1242,8 @@ static int virtnet_freeze(struct virtio_device *vdev)
 
 	remove_vq_common(vi);
 
+	flush_work(&vi->config_work);
+
 	return 0;
 }
 
@@ -1215,6 +1264,10 @@ static int virtnet_restore(struct virtio_device *vdev)
 	if (!try_fill_recv(vi, GFP_KERNEL))
 		queue_delayed_work(system_nrt_wq, &vi->refill, 0);
 
+	mutex_lock(&vi->config_lock);
+	vi->config_enable = true;
+	mutex_unlock(&vi->config_lock);
+
 	return 0;
 }
 #endif
@@ -1232,6 +1285,7 @@ static unsigned int features[] = {
 	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
+	VIRTIO_NET_F_GUEST_ANNOUNCE,
 };
 
 static struct virtio_driver virtio_net_driver = {

trunk/include/linux/virtio_net.h

@@ -49,8 +49,11 @@
 #define VIRTIO_NET_F_CTRL_RX	18	/* Control channel RX mode support */
 #define VIRTIO_NET_F_CTRL_VLAN	19	/* Control channel VLAN filtering */
 #define VIRTIO_NET_F_CTRL_RX_EXTRA 20	/* Extra RX mode control support */
+#define VIRTIO_NET_F_GUEST_ANNOUNCE 21	/* Guest can announce device on the
+					 * network */
 
 #define VIRTIO_NET_S_LINK_UP	1	/* Link is up */
+#define VIRTIO_NET_S_ANNOUNCE	2	/* Announcement is needed */
 
 struct virtio_net_config {
 	/* The config defining mac address (if VIRTIO_NET_F_MAC) */
@@ -152,4 +155,15 @@ struct virtio_net_ctrl_mac {
  #define VIRTIO_NET_CTRL_VLAN_ADD             0
  #define VIRTIO_NET_CTRL_VLAN_DEL             1
 
+/*
+ * Control link announce acknowledgement
+ *
+ * The command VIRTIO_NET_CTRL_ANNOUNCE_ACK is used to indicate that
+ * driver has recevied the notification; device would clear the
+ * VIRTIO_NET_S_ANNOUNCE bit in the status field after it receives
+ * this command.
+ */
+#define VIRTIO_NET_CTRL_ANNOUNCE       3
+ #define VIRTIO_NET_CTRL_ANNOUNCE_ACK         0
+
 #endif /* _LINUX_VIRTIO_NET_H */