netvsc: fix warnings reported by lockdep

This includes a bunch of fixups for issues reported by
lockdep.
   * ethtool routines can assume RTNL
   * send is done with RCU lock (and BH disable)
   * avoid refetching internal device struct (netvsc)
     instead pass it as a parameter.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 06f39a9..94c00ac 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -832,7 +832,7 @@
 		struct sk_buff *skb)
 {
 	struct netvsc_device *net_device
-		= rcu_dereference_rtnl(ndev_ctx->nvdev);
+		= rcu_dereference_bh(ndev_ctx->nvdev);
 	struct hv_device *device = ndev_ctx->device_ctx;
 	int ret = 0;
 	struct netvsc_channel *nvchan;