hv_netvsc: get rid of struct net_device pointer in struct netvsc_device
[cascardo/linux.git] / drivers / net / hyperv / netvsc_drv.c
index b8121eb..7325d69 100644 (file)
@@ -67,18 +67,19 @@ static void do_set_multicast(struct work_struct *w)
 {
        struct net_device_context *ndevctx =
                container_of(w, struct net_device_context, work);
-       struct netvsc_device *nvdev;
+       struct hv_device *device_obj = ndevctx->device_ctx;
+       struct net_device *ndev = hv_get_drvdata(device_obj);
+       struct netvsc_device *nvdev = ndevctx->nvdev;
        struct rndis_device *rdev;
 
-       nvdev = hv_get_drvdata(ndevctx->device_ctx);
-       if (nvdev == NULL || nvdev->ndev == NULL)
+       if (!nvdev)
                return;
 
        rdev = nvdev->extension;
        if (rdev == NULL)
                return;
 
-       if (nvdev->ndev->flags & IFF_PROMISC)
+       if (ndev->flags & IFF_PROMISC)
                rndis_filter_set_packet_filter(rdev,
                        NDIS_PACKET_TYPE_PROMISCUOUS);
        else
@@ -99,7 +100,7 @@ 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 netvsc_device *nvdev = net_device_ctx->nvdev;
        struct rndis_device *rdev;
        int ret = 0;
 
@@ -114,7 +115,6 @@ static int netvsc_open(struct net_device *net)
 
        netif_tx_wake_all_queues(net);
 
-       nvdev = hv_get_drvdata(device_obj);
        rdev = nvdev->extension;
        if (!rdev->link_state)
                netif_carrier_on(net);
@@ -126,7 +126,7 @@ static int netvsc_close(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 = hv_get_drvdata(device_obj);
+       struct netvsc_device *nvdev = net_device_ctx->nvdev;
        int ret;
        u32 aread, awrite, i, msec = 10, retry = 0, retry_max = 20;
        struct vmbus_channel *chn;
@@ -205,8 +205,7 @@ static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
                        void *accel_priv, select_queue_fallback_t fallback)
 {
        struct net_device_context *net_device_ctx = netdev_priv(ndev);
-       struct hv_device *hdev =  net_device_ctx->device_ctx;
-       struct netvsc_device *nvsc_dev = hv_get_drvdata(hdev);
+       struct netvsc_device *nvsc_dev = net_device_ctx->nvdev;
        u32 hash;
        u16 q_idx = 0;
 
@@ -580,7 +579,6 @@ void netvsc_linkstatus_callback(struct hv_device *device_obj,
        struct rndis_indicate_status *indicate = &resp->msg.indicate_status;
        struct net_device *net;
        struct net_device_context *ndev_ctx;
-       struct netvsc_device *net_device;
        struct netvsc_reconfig *event;
        unsigned long flags;
 
@@ -590,8 +588,7 @@ void netvsc_linkstatus_callback(struct hv_device *device_obj,
            indicate->status != RNDIS_STATUS_MEDIA_DISCONNECT)
                return;
 
-       net_device = hv_get_drvdata(device_obj);
-       net = net_device->ndev;
+       net = hv_get_drvdata(device_obj);
 
        if (!net || net->reg_state != NETREG_REGISTERED)
                return;
@@ -610,42 +607,24 @@ void netvsc_linkstatus_callback(struct hv_device *device_obj,
        schedule_delayed_work(&ndev_ctx->dwork, 0);
 }
 
-/*
- * netvsc_recv_callback -  Callback when we receive a packet from the
- * "wire" on the specified device.
- */
-int netvsc_recv_callback(struct hv_device *device_obj,
+
+static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
                                struct hv_netvsc_packet *packet,
-                               void **data,
                                struct ndis_tcp_ip_checksum_info *csum_info,
-                               struct vmbus_channel *channel,
-                               u16 vlan_tci)
+                               void *data, u16 vlan_tci)
 {
-       struct net_device *net;
-       struct net_device_context *net_device_ctx;
        struct sk_buff *skb;
-       struct netvsc_stats *rx_stats;
 
-       net = ((struct netvsc_device *)hv_get_drvdata(device_obj))->ndev;
-       if (!net || net->reg_state != NETREG_REGISTERED) {
-               return NVSP_STAT_FAIL;
-       }
-       net_device_ctx = netdev_priv(net);
-       rx_stats = this_cpu_ptr(net_device_ctx->rx_stats);
-
-       /* Allocate a skb - TODO direct I/O to pages? */
        skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
-       if (unlikely(!skb)) {
-               ++net->stats.rx_dropped;
-               return NVSP_STAT_FAIL;
-       }
+       if (!skb)
+               return skb;
 
        /*
         * Copy to skb. This copy is needed here since the memory pointed by
         * hv_netvsc_packet cannot be deallocated
         */
-       memcpy(skb_put(skb, packet->total_data_buflen), *data,
-               packet->total_data_buflen);
+       memcpy(skb_put(skb, packet->total_data_buflen), data,
+              packet->total_data_buflen);
 
        skb->protocol = eth_type_trans(skb, net);
        if (csum_info) {
@@ -663,6 +642,74 @@ int netvsc_recv_callback(struct hv_device *device_obj,
                __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
                                       vlan_tci);
 
+       return skb;
+}
+
+/*
+ * netvsc_recv_callback -  Callback when we receive a packet from the
+ * "wire" on the specified device.
+ */
+int netvsc_recv_callback(struct hv_device *device_obj,
+                               struct hv_netvsc_packet *packet,
+                               void **data,
+                               struct ndis_tcp_ip_checksum_info *csum_info,
+                               struct vmbus_channel *channel,
+                               u16 vlan_tci)
+{
+       struct net_device *net = hv_get_drvdata(device_obj);
+       struct net_device_context *net_device_ctx = netdev_priv(net);
+       struct sk_buff *skb;
+       struct sk_buff *vf_skb;
+       struct netvsc_stats *rx_stats;
+       struct netvsc_device *netvsc_dev = net_device_ctx->nvdev;
+       u32 bytes_recvd = packet->total_data_buflen;
+       int ret = 0;
+
+       if (!net || net->reg_state != NETREG_REGISTERED)
+               return NVSP_STAT_FAIL;
+
+       if (READ_ONCE(netvsc_dev->vf_inject)) {
+               atomic_inc(&netvsc_dev->vf_use_cnt);
+               if (!READ_ONCE(netvsc_dev->vf_inject)) {
+                       /*
+                        * We raced; just move on.
+                        */
+                       atomic_dec(&netvsc_dev->vf_use_cnt);
+                       goto vf_injection_done;
+               }
+
+               /*
+                * Inject this packet into the VF inerface.
+                * On Hyper-V, multicast and brodcast packets
+                * are only delivered on the synthetic interface
+                * (after subjecting these to policy filters on
+                * the host). Deliver these via the VF interface
+                * in the guest.
+                */
+               vf_skb = netvsc_alloc_recv_skb(netvsc_dev->vf_netdev, packet,
+                                              csum_info, *data, vlan_tci);
+               if (vf_skb != NULL) {
+                       ++netvsc_dev->vf_netdev->stats.rx_packets;
+                       netvsc_dev->vf_netdev->stats.rx_bytes += bytes_recvd;
+                       netif_receive_skb(vf_skb);
+               } else {
+                       ++net->stats.rx_dropped;
+                       ret = NVSP_STAT_FAIL;
+               }
+               atomic_dec(&netvsc_dev->vf_use_cnt);
+               return ret;
+       }
+
+vf_injection_done:
+       net_device_ctx = netdev_priv(net);
+       rx_stats = this_cpu_ptr(net_device_ctx->rx_stats);
+
+       /* Allocate a skb - TODO direct I/O to pages? */
+       skb = netvsc_alloc_recv_skb(net, packet, csum_info, *data, vlan_tci);
+       if (unlikely(!skb)) {
+               ++net->stats.rx_dropped;
+               return NVSP_STAT_FAIL;
+       }
        skb_record_rx_queue(skb, channel->
                            offermsg.offer.sub_channel_index);
 
@@ -692,8 +739,7 @@ static void netvsc_get_channels(struct net_device *net,
                                struct ethtool_channels *channel)
 {
        struct net_device_context *net_device_ctx = netdev_priv(net);
-       struct hv_device *dev = net_device_ctx->device_ctx;
-       struct netvsc_device *nvdev = hv_get_drvdata(dev);
+       struct netvsc_device *nvdev = net_device_ctx->nvdev;
 
        if (nvdev) {
                channel->max_combined   = nvdev->max_chn;
@@ -706,7 +752,7 @@ static int netvsc_set_channels(struct net_device *net,
 {
        struct net_device_context *net_device_ctx = netdev_priv(net);
        struct hv_device *dev = net_device_ctx->device_ctx;
-       struct netvsc_device *nvdev = hv_get_drvdata(dev);
+       struct netvsc_device *nvdev = net_device_ctx->nvdev;
        struct netvsc_device_info device_info;
        u32 num_chn;
        u32 max_chn;
@@ -742,14 +788,11 @@ static int netvsc_set_channels(struct net_device *net,
                goto out;
 
  do_set:
-       nvdev->start_remove = true;
+       net_device_ctx->start_remove = true;
        rndis_filter_device_remove(dev);
 
        nvdev->num_chn = channels->combined_count;
 
-       net_device_ctx->device_ctx = dev;
-       hv_set_drvdata(dev, net);
-
        memset(&device_info, 0, sizeof(device_info));
        device_info.num_chn = nvdev->num_chn; /* passed to RNDIS */
        device_info.ring_size = ring_size;
@@ -764,7 +807,7 @@ static int netvsc_set_channels(struct net_device *net,
                goto recover;
        }
 
-       nvdev = hv_get_drvdata(dev);
+       nvdev = net_device_ctx->nvdev;
 
        ret = netif_set_real_num_tx_queues(net, nvdev->num_chn);
        if (ret) {
@@ -786,6 +829,9 @@ static int netvsc_set_channels(struct net_device *net,
 
  out:
        netvsc_open(net);
+       net_device_ctx->start_remove = false;
+       /* We may have missed link change notifications */
+       schedule_delayed_work(&net_device_ctx->dwork, 0);
 
        return ret;
 
@@ -854,8 +900,8 @@ static int netvsc_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 {
        struct net_device_context *ndevctx = netdev_priv(ndev);
-       struct hv_device *hdev =  ndevctx->device_ctx;
-       struct netvsc_device *nvdev = hv_get_drvdata(hdev);
+       struct netvsc_device *nvdev = ndevctx->nvdev;
+       struct hv_device *hdev = ndevctx->device_ctx;
        struct netvsc_device_info device_info;
        int limit = ETH_DATA_LEN;
        u32 num_chn;
@@ -876,14 +922,11 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 
        num_chn = nvdev->num_chn;
 
-       nvdev->start_remove = true;
+       ndevctx->start_remove = true;
        rndis_filter_device_remove(hdev);
 
        ndev->mtu = mtu;
 
-       ndevctx->device_ctx = hdev;
-       hv_set_drvdata(hdev, ndev);
-
        memset(&device_info, 0, sizeof(device_info));
        device_info.ring_size = ring_size;
        device_info.num_chn = num_chn;
@@ -892,6 +935,10 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 
 out:
        netvsc_open(ndev);
+       ndevctx->start_remove = false;
+
+       /* We may have missed link change notifications */
+       schedule_delayed_work(&ndevctx->dwork, 0);
 
        return ret;
 }
@@ -1004,18 +1051,22 @@ static const struct net_device_ops device_ops = {
  */
 static void netvsc_link_change(struct work_struct *w)
 {
-       struct net_device_context *ndev_ctx;
-       struct net_device *net;
+       struct net_device_context *ndev_ctx =
+               container_of(w, struct net_device_context, dwork.work);
+       struct hv_device *device_obj = ndev_ctx->device_ctx;
+       struct net_device *net = hv_get_drvdata(device_obj);
        struct netvsc_device *net_device;
        struct rndis_device *rdev;
        struct netvsc_reconfig *event = NULL;
        bool notify = false, reschedule = false;
        unsigned long flags, next_reconfig, delay;
 
-       ndev_ctx = container_of(w, struct net_device_context, dwork.work);
-       net_device = hv_get_drvdata(ndev_ctx->device_ctx);
+       rtnl_lock();
+       if (ndev_ctx->start_remove)
+               goto out_unlock;
+
+       net_device = ndev_ctx->nvdev;
        rdev = net_device->extension;
-       net = net_device->ndev;
 
        next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
        if (time_is_after_jiffies(next_reconfig)) {
@@ -1026,7 +1077,7 @@ static void netvsc_link_change(struct work_struct *w)
                delay = next_reconfig - jiffies;
                delay = delay < LINKCHANGE_INT ? delay : LINKCHANGE_INT;
                schedule_delayed_work(&ndev_ctx->dwork, delay);
-               return;
+               goto out_unlock;
        }
        ndev_ctx->last_reconfig = jiffies;
 
@@ -1040,9 +1091,7 @@ static void netvsc_link_change(struct work_struct *w)
        spin_unlock_irqrestore(&ndev_ctx->lock, flags);
 
        if (!event)
-               return;
-
-       rtnl_lock();
+               goto out_unlock;
 
        switch (event->event) {
                /* Only the following events are possible due to the check in
@@ -1074,7 +1123,7 @@ static void netvsc_link_change(struct work_struct *w)
                        netif_tx_stop_all_queues(net);
                        event->event = RNDIS_STATUS_MEDIA_CONNECT;
                        spin_lock_irqsave(&ndev_ctx->lock, flags);
-                       list_add_tail(&event->list, &ndev_ctx->reconfig_events);
+                       list_add(&event->list, &ndev_ctx->reconfig_events);
                        spin_unlock_irqrestore(&ndev_ctx->lock, flags);
                        reschedule = true;
                }
@@ -1091,6 +1140,11 @@ static void netvsc_link_change(struct work_struct *w)
         */
        if (reschedule)
                schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT);
+
+       return;
+
+out_unlock:
+       rtnl_unlock();
 }
 
 static void netvsc_free_netdev(struct net_device *netdev)
@@ -1102,6 +1156,192 @@ static void netvsc_free_netdev(struct net_device *netdev)
        free_netdev(netdev);
 }
 
+static void netvsc_notify_peers(struct work_struct *wrk)
+{
+       struct garp_wrk *gwrk;
+
+       gwrk = container_of(wrk, struct garp_wrk, dwrk);
+
+       netdev_notify_peers(gwrk->netdev);
+
+       atomic_dec(&gwrk->netvsc_dev->vf_use_cnt);
+}
+
+static struct net_device *get_netvsc_net_device(char *mac)
+{
+       struct net_device *dev, *found = NULL;
+       int rtnl_locked;
+
+       rtnl_locked = rtnl_trylock();
+
+       for_each_netdev(&init_net, dev) {
+               if (memcmp(dev->dev_addr, mac, ETH_ALEN) == 0) {
+                       if (dev->netdev_ops != &device_ops)
+                               continue;
+                       found = dev;
+                       break;
+               }
+       }
+       if (rtnl_locked)
+               rtnl_unlock();
+
+       return found;
+}
+
+static int netvsc_register_vf(struct net_device *vf_netdev)
+{
+       struct net_device *ndev;
+       struct net_device_context *net_device_ctx;
+       struct netvsc_device *netvsc_dev;
+       const struct ethtool_ops *eth_ops = vf_netdev->ethtool_ops;
+
+       if (eth_ops == NULL || eth_ops == &ethtool_ops)
+               return NOTIFY_DONE;
+
+       /*
+        * We will use the MAC address to locate the synthetic interface to
+        * associate with the VF interface. If we don't find a matching
+        * synthetic interface, move on.
+        */
+       ndev = get_netvsc_net_device(vf_netdev->dev_addr);
+       if (!ndev)
+               return NOTIFY_DONE;
+
+       net_device_ctx = netdev_priv(ndev);
+       netvsc_dev = net_device_ctx->nvdev;
+       if (netvsc_dev == NULL)
+               return NOTIFY_DONE;
+
+       netdev_info(ndev, "VF registering: %s\n", vf_netdev->name);
+       /*
+        * Take a reference on the module.
+        */
+       try_module_get(THIS_MODULE);
+       netvsc_dev->vf_netdev = vf_netdev;
+       return NOTIFY_OK;
+}
+
+
+static int netvsc_vf_up(struct net_device *vf_netdev)
+{
+       struct net_device *ndev;
+       struct netvsc_device *netvsc_dev;
+       const struct ethtool_ops *eth_ops = vf_netdev->ethtool_ops;
+       struct net_device_context *net_device_ctx;
+
+       if (eth_ops == &ethtool_ops)
+               return NOTIFY_DONE;
+
+       ndev = get_netvsc_net_device(vf_netdev->dev_addr);
+       if (!ndev)
+               return NOTIFY_DONE;
+
+       net_device_ctx = netdev_priv(ndev);
+       netvsc_dev = net_device_ctx->nvdev;
+
+       if ((netvsc_dev == NULL) || (netvsc_dev->vf_netdev == NULL))
+               return NOTIFY_DONE;
+
+       netdev_info(ndev, "VF up: %s\n", vf_netdev->name);
+       netvsc_dev->vf_inject = true;
+
+       /*
+        * Open the device before switching data path.
+        */
+       rndis_filter_open(net_device_ctx->device_ctx);
+
+       /*
+        * notify the host to switch the data path.
+        */
+       netvsc_switch_datapath(ndev, true);
+       netdev_info(ndev, "Data path switched to VF: %s\n", vf_netdev->name);
+
+       netif_carrier_off(ndev);
+
+       /*
+        * Now notify peers. We are scheduling work to
+        * notify peers; take a reference to prevent
+        * the VF interface from vanishing.
+        */
+       atomic_inc(&netvsc_dev->vf_use_cnt);
+       net_device_ctx->gwrk.netdev = vf_netdev;
+       net_device_ctx->gwrk.netvsc_dev = netvsc_dev;
+       schedule_work(&net_device_ctx->gwrk.dwrk);
+
+       return NOTIFY_OK;
+}
+
+
+static int netvsc_vf_down(struct net_device *vf_netdev)
+{
+       struct net_device *ndev;
+       struct netvsc_device *netvsc_dev;
+       struct net_device_context *net_device_ctx;
+       const struct ethtool_ops *eth_ops = vf_netdev->ethtool_ops;
+
+       if (eth_ops == &ethtool_ops)
+               return NOTIFY_DONE;
+
+       ndev = get_netvsc_net_device(vf_netdev->dev_addr);
+       if (!ndev)
+               return NOTIFY_DONE;
+
+       net_device_ctx = netdev_priv(ndev);
+       netvsc_dev = net_device_ctx->nvdev;
+
+       if ((netvsc_dev == NULL) || (netvsc_dev->vf_netdev == NULL))
+               return NOTIFY_DONE;
+
+       netdev_info(ndev, "VF down: %s\n", vf_netdev->name);
+       netvsc_dev->vf_inject = false;
+       /*
+        * Wait for currently active users to
+        * drain out.
+        */
+
+       while (atomic_read(&netvsc_dev->vf_use_cnt) != 0)
+               udelay(50);
+       netvsc_switch_datapath(ndev, false);
+       netdev_info(ndev, "Data path switched from VF: %s\n", vf_netdev->name);
+       rndis_filter_close(net_device_ctx->device_ctx);
+       netif_carrier_on(ndev);
+       /*
+        * Notify peers.
+        */
+       atomic_inc(&netvsc_dev->vf_use_cnt);
+       net_device_ctx->gwrk.netdev = ndev;
+       net_device_ctx->gwrk.netvsc_dev = netvsc_dev;
+       schedule_work(&net_device_ctx->gwrk.dwrk);
+
+       return NOTIFY_OK;
+}
+
+
+static int netvsc_unregister_vf(struct net_device *vf_netdev)
+{
+       struct net_device *ndev;
+       struct netvsc_device *netvsc_dev;
+       const struct ethtool_ops *eth_ops = vf_netdev->ethtool_ops;
+       struct net_device_context *net_device_ctx;
+
+       if (eth_ops == &ethtool_ops)
+               return NOTIFY_DONE;
+
+       ndev = get_netvsc_net_device(vf_netdev->dev_addr);
+       if (!ndev)
+               return NOTIFY_DONE;
+
+       net_device_ctx = netdev_priv(ndev);
+       netvsc_dev = net_device_ctx->nvdev;
+       if (netvsc_dev == NULL)
+               return NOTIFY_DONE;
+       netdev_info(ndev, "VF unregistering: %s\n", vf_netdev->name);
+
+       netvsc_dev->vf_netdev = NULL;
+       module_put(THIS_MODULE);
+       return NOTIFY_OK;
+}
+
 static int netvsc_probe(struct hv_device *dev,
                        const struct hv_vmbus_device_id *dev_id)
 {
@@ -1138,8 +1378,12 @@ static int netvsc_probe(struct hv_device *dev,
        }
 
        hv_set_drvdata(dev, net);
+
+       net_device_ctx->start_remove = false;
+
        INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
        INIT_WORK(&net_device_ctx->work, do_set_multicast);
+       INIT_WORK(&net_device_ctx->gwrk.dwrk, netvsc_notify_peers);
 
        spin_lock_init(&net_device_ctx->lock);
        INIT_LIST_HEAD(&net_device_ctx->reconfig_events);
@@ -1168,7 +1412,7 @@ static int netvsc_probe(struct hv_device *dev,
        }
        memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
 
-       nvdev = hv_get_drvdata(dev);
+       nvdev = net_device_ctx->nvdev;
        netif_set_real_num_tx_queues(net, nvdev->num_chn);
        netif_set_real_num_rx_queues(net, nvdev->num_chn);
 
@@ -1190,17 +1434,19 @@ static int netvsc_remove(struct hv_device *dev)
        struct net_device_context *ndev_ctx;
        struct netvsc_device *net_device;
 
-       net_device = hv_get_drvdata(dev);
-       net = net_device->ndev;
+       net = hv_get_drvdata(dev);
 
        if (net == NULL) {
                dev_err(&dev->device, "No net device to remove\n");
                return 0;
        }
 
-       net_device->start_remove = true;
 
        ndev_ctx = netdev_priv(net);
+       net_device = ndev_ctx->nvdev;
+
+       ndev_ctx->start_remove = true;
+
        cancel_delayed_work_sync(&ndev_ctx->dwork);
        cancel_work_sync(&ndev_ctx->work);
 
@@ -1215,6 +1461,8 @@ static int netvsc_remove(struct hv_device *dev)
         */
        rndis_filter_device_remove(dev);
 
+       hv_set_drvdata(dev, NULL);
+
        netvsc_free_netdev(net);
        return 0;
 }
@@ -1235,19 +1483,58 @@ static struct  hv_driver netvsc_drv = {
        .remove = netvsc_remove,
 };
 
+
+/*
+ * On Hyper-V, every VF interface is matched with a corresponding
+ * synthetic interface. The synthetic interface is presented first
+ * to the guest. When the corresponding VF instance is registered,
+ * we will take care of switching the data path.
+ */
+static int netvsc_netdev_event(struct notifier_block *this,
+                              unsigned long event, void *ptr)
+{
+       struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
+
+       switch (event) {
+       case NETDEV_REGISTER:
+               return netvsc_register_vf(event_dev);
+       case NETDEV_UNREGISTER:
+               return netvsc_unregister_vf(event_dev);
+       case NETDEV_UP:
+               return netvsc_vf_up(event_dev);
+       case NETDEV_DOWN:
+               return netvsc_vf_down(event_dev);
+       default:
+               return NOTIFY_DONE;
+       }
+}
+
+static struct notifier_block netvsc_netdev_notifier = {
+       .notifier_call = netvsc_netdev_event,
+};
+
 static void __exit netvsc_drv_exit(void)
 {
+       unregister_netdevice_notifier(&netvsc_netdev_notifier);
        vmbus_driver_unregister(&netvsc_drv);
 }
 
 static int __init netvsc_drv_init(void)
 {
+       int ret;
+
        if (ring_size < RING_SIZE_MIN) {
                ring_size = RING_SIZE_MIN;
                pr_info("Increased ring_size to %d (min allowed)\n",
                        ring_size);
        }
-       return vmbus_driver_register(&netvsc_drv);
+       ret = vmbus_driver_register(&netvsc_drv);
+
+       if (ret)
+               return ret;
+
+       register_netdevice_notifier(&netvsc_netdev_notifier);
+       return 0;
 }
 
 MODULE_LICENSE("GPL");