drivers/net: remove some rcu sparse warnings

Add missing __rcu annotations and helpers.
minor : Fix some rcu_dereference() calls in macvtap

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bnx2x/bnx2x_main.c b/drivers/net/bnx2x/bnx2x_main.c
index 8cdcf5b..a2a1bc4 100644
--- a/drivers/net/bnx2x/bnx2x_main.c
+++ b/drivers/net/bnx2x/bnx2x_main.c
@@ -9862,7 +9862,8 @@
 	int rc = 0;
 
 	mutex_lock(&bp->cnic_mutex);
-	c_ops = bp->cnic_ops;
+	c_ops = rcu_dereference_protected(bp->cnic_ops,
+					  lockdep_is_held(&bp->cnic_mutex));
 	if (c_ops)
 		rc = c_ops->cnic_ctl(bp->cnic_data, ctl);
 	mutex_unlock(&bp->cnic_mutex);