hv_netvsc: pair VF based on serial number

Matching network device based on MAC address is problematic
since a non VF network device can be creted with a duplicate MAC
address causing confusion and problems.  The VMBus API does provide
a serial number that is a better matching method.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 36 insertions, 25 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 915fbd66a02b..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;