nfp: allow converting representor's netdev into nfp_port

Based on struct net_device_ops figure out if netdev is a nfp_repr.
Use this knowledge to convert netdev directly to nfp_port.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_repr.c

@@ -249,7 +249,7 @@ static int nfp_repr_open(struct net_device *netdev)
 	return nfp_app_repr_open(repr->app, repr);
 }
 
-static const struct net_device_ops nfp_repr_netdev_ops = {
+const struct net_device_ops nfp_repr_netdev_ops = {
 	.ndo_open		= nfp_repr_open,
 	.ndo_stop		= nfp_repr_stop,
 	.ndo_start_xmit		= nfp_repr_xmit,

drivers/net/ethernet/netronome/nfp/nfp_net_repr.h

@@ -97,6 +97,13 @@ enum nfp_repr_type {
 };
 #define NFP_REPR_TYPE_MAX (__NFP_REPR_TYPE_MAX - 1)
 
+extern const struct net_device_ops nfp_repr_netdev_ops;
+
+static inline bool nfp_netdev_is_nfp_repr(struct net_device *netdev)
+{
+	return netdev->netdev_ops == &nfp_repr_netdev_ops;
+}
+
 void nfp_repr_inc_rx_stats(struct net_device *netdev, unsigned int len);
 int nfp_repr_init(struct nfp_app *app, struct net_device *netdev,
 		  u32 cmsg_port_id, struct nfp_port *port,

drivers/net/ethernet/netronome/nfp/nfp_port.c

@@ -42,13 +42,21 @@
 
 struct nfp_port *nfp_port_from_netdev(struct net_device *netdev)
 {
-	struct nfp_net *nn;
+	if (nfp_netdev_is_nfp_net(netdev)) {
+		struct nfp_net *nn = netdev_priv(netdev);
 
-	if (WARN_ON(!nfp_netdev_is_nfp_net(netdev)))
-		return NULL;
-	nn = netdev_priv(netdev);
+		return nn->port;
+	}
 
-	return nn->port;
+	if (nfp_netdev_is_nfp_repr(netdev)) {
+		struct nfp_repr *repr = netdev_priv(netdev);
+
+		return repr->port;
+	}
+
+	WARN(1, "Unknown netdev type for nfp_port\n");
+
+	return NULL;
 }
 
 struct nfp_port *