2 files changed, 49 insertions, 32 deletions

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 31c3d77b4733..fe01e141c8f8 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -1203,6 +1203,9 @@ static void netvsc_send_vf(struct net_device *ndev,
 
         net_device_ctx->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
         net_device_ctx->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
+        netdev_info(ndev, "VF slot %u %s\n",
+                    net_device_ctx->vf_serial,
+                    net_device_ctx->vf_alloc ? "added" : "removed");
 }
 
 static  void netvsc_receive_inband(struct net_device *ndev,
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 1121a1ec407c..3af6d8d15233 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1894,20 +1894,6 @@ out_unlock:
         rtnl_unlock();
 }
 
-static struct net_device *get_netvsc_bymac(const u8 *mac)
-{
-        struct net_device_context *ndev_ctx;
-
-        list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {
-                struct net_device *dev = hv_get_drvdata(ndev_ctx->device_ctx);
-
-                if (ether_addr_equal(mac, dev->perm_addr))
-                        return dev;
-        }
-
-        return NULL;
-}
-
 static struct net_device *get_netvsc_byref(struct net_device *vf_netdev)
 {
         struct net_device_context *net_device_ctx;
@@ -2036,26 +2022,48 @@ static void netvsc_vf_setup(struct work_struct *w)
         rtnl_unlock();
 }
 
+/* Find netvsc by VMBus serial number.
+ * The PCI hyperv controller records the serial number as the slot.
+ */
+static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
+{
+        struct device *parent = vf_netdev->dev.parent;
+        struct net_device_context *ndev_ctx;
+        struct pci_dev *pdev;
+
+        if (!parent || !dev_is_pci(parent))
+                return NULL; /* not a PCI device */
+
+        pdev = to_pci_dev(parent);
+        if (!pdev->slot) {
+                netdev_notice(vf_netdev, "no PCI slot information\n");
+                return NULL;
+        }
+
+        list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {
+                if (!ndev_ctx->vf_alloc)
+                        continue;
+
+                if (ndev_ctx->vf_serial == pdev->slot->number)
+                        return hv_get_drvdata(ndev_ctx->device_ctx);
+        }
+
+        netdev_notice(vf_netdev,
+                      "no netdev found for slot %u\n", pdev->slot->number);
+        return NULL;
+}
+
 static int netvsc_register_vf(struct net_device *vf_netdev)
 {
-        struct net_device *ndev;
         struct net_device_context *net_device_ctx;
-        struct device *pdev = vf_netdev->dev.parent;
         struct netvsc_device *netvsc_dev;
+        struct net_device *ndev;
         int ret;
 
         if (vf_netdev->addr_len != ETH_ALEN)
                 return NOTIFY_DONE;
 
-        if (!pdev || !dev_is_pci(pdev) || dev_is_pf(pdev))
-                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_bymac(vf_netdev->perm_addr);
+        ndev = get_netvsc_byslot(vf_netdev);
         if (!ndev)
                 return NOTIFY_DONE;
 
@@ -2206,6 +2214,16 @@ static int netvsc_probe(struct hv_device *dev,
 
         memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
 
+        /* We must get rtnl lock before scheduling nvdev->subchan_work,
+         * otherwise netvsc_subchan_work() can get rtnl lock first and wait
+         * all subchannels to show up, but that may not happen because
+         * netvsc_probe() can't get rtnl lock and as a result vmbus_onoffer()
+         * -> ... -> device_add() -> ... -> __device_attach() can't get
+         * the device lock, so all the subchannels can't be processed --
+         * finally netvsc_subchan_work() hangs for ever.
+         */
+        rtnl_lock();
+
         if (nvdev->num_chn > 1)
                 schedule_work(&nvdev->subchan_work);
 
@@ -2224,7 +2242,6 @@ static int netvsc_probe(struct hv_device *dev,
         else
                 net->max_mtu = ETH_DATA_LEN;
 
-        rtnl_lock();
         ret = register_netdevice(net);
         if (ret != 0) {
                 pr_err("Unable to register netdev.\n");
@@ -2263,17 +2280,15 @@ static int netvsc_remove(struct hv_device *dev)
 
         cancel_delayed_work_sync(&ndev_ctx->dwork);
 
-        rcu_read_lock();
-        nvdev = rcu_dereference(ndev_ctx->nvdev);
-
-        if  (nvdev)
+        rtnl_lock();
+        nvdev = rtnl_dereference(ndev_ctx->nvdev);
+        if (nvdev)
                 cancel_work_sync(&nvdev->subchan_work);
 
         /*
          * Call to the vsc driver to let it know that the device is being
          * removed. Also blocks mtu and channel changes.
          */
-        rtnl_lock();
         vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
         if (vf_netdev)
                 netvsc_unregister_vf(vf_netdev);
@@ -2285,7 +2300,6 @@ static int netvsc_remove(struct hv_device *dev)
         list_del(&ndev_ctx->list);
 
         rtnl_unlock();
-        rcu_read_unlock();
 
         hv_set_drvdata(dev, NULL);