hv_netvsc: Cache the current data path to avoid duplicate call and message

The previous change "hv_netvsc: Switch the data path at the right time
during hibernation" adds the call of netvsc_vf_changed() upon
NETDEV_CHANGE, so it's necessary to avoid the duplicate call and message
when the VF is brought UP or DOWN.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 2181d4538ab70712ddebd7fda12ca9a8c27b45c1..ff33f27cdcd315d506239358351f46a6fd707134 100644 (file)
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -974,6 +974,9 @@ struct net_device_context {
        /* Serial number of the VF to team with */
        u32 vf_serial;
 
+       /* Is the current data path through the VF NIC? */
+       bool  data_path_is_vf;
+
        /* Used to temporarily save the config info across hibernation */
        struct netvsc_device_info *saved_netvsc_dev_info;
 };

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 4a25886e23467143897eb7a9e4225af763cebca6..b7db3766f5b951969b8693eb0f99a4571c1922cd 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2366,7 +2366,16 @@ static int netvsc_register_vf(struct net_device *vf_netdev)
        return NOTIFY_OK;
 }
 
-/* VF up/down change detected, schedule to change data path */
+/* Change the data path when VF UP/DOWN/CHANGE are detected.
+ *
+ * Typically a UP or DOWN event is followed by a CHANGE event, so
+ * net_device_ctx->data_path_is_vf is used to cache the current data path
+ * to avoid the duplicate call of netvsc_switch_datapath() and the duplicate
+ * message.
+ *
+ * During hibernation, if a VF NIC driver (e.g. mlx5) preserves the network
+ * interface, there is only the CHANGE event and no UP or DOWN event.
+ */
 static int netvsc_vf_changed(struct net_device *vf_netdev)
 {
        struct net_device_context *net_device_ctx;
@@ -2383,6 +2392,10 @@ static int netvsc_vf_changed(struct net_device *vf_netdev)
        if (!netvsc_dev)
                return NOTIFY_DONE;
 
+       if (net_device_ctx->data_path_is_vf == vf_is_up)
+               return NOTIFY_OK;
+       net_device_ctx->data_path_is_vf = vf_is_up;
+
        netvsc_switch_datapath(ndev, vf_is_up);
        netdev_info(ndev, "Data path switched %s VF: %s\n",
                    vf_is_up ? "to" : "from", vf_netdev->name);
@@ -2624,6 +2637,12 @@ static int netvsc_resume(struct hv_device *dev)
        rtnl_lock();
 
        net_device_ctx = netdev_priv(net);
+
+       /* Reset the data path to the netvsc NIC before re-opening the vmbus
+        * channel. Later netvsc_netdev_event() will switch the data path to
+        * the VF upon the UP or CHANGE event.
+        */
+       net_device_ctx->data_path_is_vf = false;
        device_info = net_device_ctx->saved_netvsc_dev_info;
 
        ret = netvsc_attach(net, device_info);