nfp: modify app MTU setting callbacks

Rename the 'change_mtu' app callback to 'check_mtu'. This is called
whenever an MTU change is requested on a netdev. It can reject the
change but is not responsible for implementing it.

Introduce a new 'repr_change_mtu' app callback that is hit when the MTU
of a repr is to be changed. This is responsible for performing the MTU
change and verifying it.
Signed-off-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/bpf/main.c

@@ -221,7 +221,7 @@ static int nfp_bpf_setup_tc(struct nfp_app *app, struct net_device *netdev,
 }
 
 static int
-nfp_bpf_change_mtu(struct nfp_app *app, struct net_device *netdev, int new_mtu)
+nfp_bpf_check_mtu(struct nfp_app *app, struct net_device *netdev, int new_mtu)
 {
 	struct nfp_net *nn = netdev_priv(netdev);
 	unsigned int max_mtu;
@@ -413,7 +413,7 @@ const struct nfp_app_type app_bpf = {
 	.init		= nfp_bpf_init,
 	.clean		= nfp_bpf_clean,
 
-	.change_mtu	= nfp_bpf_change_mtu,
+	.check_mtu	= nfp_bpf_check_mtu,
 
 	.extra_cap	= nfp_bpf_extra_cap,
 

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

@@ -86,8 +86,8 @@ extern const struct nfp_app_type app_flower;
  * @repr_clean:	representor about to be unregistered
  * @repr_open:	representor netdev open callback
  * @repr_stop:	representor netdev stop callback
- * @change_mtu:	MTU change on a netdev has been requested (veto-only, change
- *		is not guaranteed to be committed)
+ * @check_mtu:	MTU change request on a netdev (verify it is valid)
+ * @repr_change_mtu:	MTU change request on repr (make and verify change)
  * @start:	start application logic
  * @stop:	stop application logic
  * @ctrl_msg_rx:    control message handler
@@ -124,8 +124,10 @@ struct nfp_app_type {
 	int (*repr_open)(struct nfp_app *app, struct nfp_repr *repr);
 	int (*repr_stop)(struct nfp_app *app, struct nfp_repr *repr);
 
-	int (*change_mtu)(struct nfp_app *app, struct net_device *netdev,
-			  int new_mtu);
+	int (*check_mtu)(struct nfp_app *app, struct net_device *netdev,
+			 int new_mtu);
+	int (*repr_change_mtu)(struct nfp_app *app, struct net_device *netdev,
+			       int new_mtu);
 
 	int (*start)(struct nfp_app *app);
 	void (*stop)(struct nfp_app *app);
@@ -247,11 +249,20 @@ nfp_app_repr_clean(struct nfp_app *app, struct net_device *netdev)
 }
 
 static inline int
-nfp_app_change_mtu(struct nfp_app *app, struct net_device *netdev, int new_mtu)
+nfp_app_check_mtu(struct nfp_app *app, struct net_device *netdev, int new_mtu)
 {
-	if (!app || !app->type->change_mtu)
+	if (!app || !app->type->check_mtu)
 		return 0;
-	return app->type->change_mtu(app, netdev, new_mtu);
+	return app->type->check_mtu(app, netdev, new_mtu);
+}
+
+static inline int
+nfp_app_repr_change_mtu(struct nfp_app *app, struct net_device *netdev,
+			int new_mtu)
+{
+	if (!app || !app->type->repr_change_mtu)
+		return 0;
+	return app->type->repr_change_mtu(app, netdev, new_mtu);
 }
 
 static inline int nfp_app_start(struct nfp_app *app, struct nfp_net *ctrl)

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

@@ -3066,7 +3066,7 @@ static int nfp_net_change_mtu(struct net_device *netdev, int new_mtu)
 	struct nfp_net_dp *dp;
 	int err;
 
-	err = nfp_app_change_mtu(nn->app, netdev, new_mtu);
+	err = nfp_app_check_mtu(nn->app, netdev, new_mtu);
 	if (err)
 		return err;
 

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

@@ -196,8 +196,19 @@ nfp_repr_get_offload_stats(int attr_id, const struct net_device *dev,
 static int nfp_repr_change_mtu(struct net_device *netdev, int new_mtu)
 {
 	struct nfp_repr *repr = netdev_priv(netdev);
+	int err;
 
-	return nfp_app_change_mtu(repr->app, netdev, new_mtu);
+	err = nfp_app_check_mtu(repr->app, netdev, new_mtu);
+	if (err)
+		return err;
+
+	err = nfp_app_repr_change_mtu(repr->app, netdev, new_mtu);
+	if (err)
+		return err;
+
+	netdev->mtu = new_mtu;
+
+	return 0;
 }
 
 static netdev_tx_t nfp_repr_xmit(struct sk_buff *skb, struct net_device *netdev)