net: switchdev: Add a helper to replay objects on a bridge port

When a front panel joins a bridge via another netdevice (typically a LAG),
the driver needs to learn about the objects configured on the bridge port.
When the bridge port is offloaded by the driver for the first time, this
can be achieved by passing a notifier to switchdev_bridge_port_offload().
The notifier is then invoked for the individual objects (such as VLANs)
configured on the bridge, and can look for the interesting ones.

Calling switchdev_bridge_port_offload() when the second port joins the
bridge lower is unnecessary, but the replay is still needed. To that end,
add a new function, switchdev_bridge_port_replay(), which does only the
replay part of the _offload() function in exactly the same way as that
function.

Cc: Jiri Pirko <[e-mail]>
Cc: Ivan Vecera <[e-mail]>
Cc: Roopa Prabhu <[e-mail]>
Cc: Nikolay Aleksandrov <[e-mail]>
Cc: [e-mail]
Signed-off-by: Petr Machata <[e-mail]>
Reviewed-by: Danielle Ratson <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/switchdev.h

···
 
 	SWITCHDEV_BRPORT_OFFLOADED,
 	SWITCHDEV_BRPORT_UNOFFLOADED,
+	SWITCHDEV_BRPORT_REPLAY,
 };
 
 struct switchdev_notifier_info {
···
 				     const void *ctx,
 				     struct notifier_block *atomic_nb,
 				     struct notifier_block *blocking_nb);
+int switchdev_bridge_port_replay(struct net_device *brport_dev,
+				 struct net_device *dev, const void *ctx,
+				 struct notifier_block *atomic_nb,
+				 struct notifier_block *blocking_nb,
+				 struct netlink_ext_ack *extack);
 
 void switchdev_deferred_process(void);
 int switchdev_port_attr_set(struct net_device *dev,

net/bridge/br.c

···
 		br_switchdev_port_unoffload(p, b->ctx, b->atomic_nb,
 					    b->blocking_nb);
 		break;
+	case SWITCHDEV_BRPORT_REPLAY:
+		brport_info = ptr;
+		b = &brport_info->brport;
+
+		err = br_switchdev_port_replay(p, b->dev, b->ctx, b->atomic_nb,
+					       b->blocking_nb, extack);
+		err = notifier_from_errno(err);
+		break;
 	}
 
 out:

net/bridge/br_private.h

···
 				 struct notifier_block *atomic_nb,
 				 struct notifier_block *blocking_nb);
 
+int br_switchdev_port_replay(struct net_bridge_port *p,
+			     struct net_device *dev, const void *ctx,
+			     struct notifier_block *atomic_nb,
+			     struct notifier_block *blocking_nb,
+			     struct netlink_ext_ack *extack);
+
 bool br_switchdev_frame_uses_tx_fwd_offload(struct sk_buff *skb);
 
 void br_switchdev_frame_set_offload_fwd_mark(struct sk_buff *skb);
···
 			    struct notifier_block *atomic_nb,
 			    struct notifier_block *blocking_nb)
 {
+}
+
+static inline int
+br_switchdev_port_replay(struct net_bridge_port *p,
+			 struct net_device *dev, const void *ctx,
+			 struct notifier_block *atomic_nb,
+			 struct notifier_block *blocking_nb,
+			 struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
 }
 
 static inline bool br_switchdev_frame_uses_tx_fwd_offload(struct sk_buff *skb)

net/bridge/br_switchdev.c

···
 
 	nbp_switchdev_del(p);
 }
+
+int br_switchdev_port_replay(struct net_bridge_port *p,
+			     struct net_device *dev, const void *ctx,
+			     struct notifier_block *atomic_nb,
+			     struct notifier_block *blocking_nb,
+			     struct netlink_ext_ack *extack)
+{
+	return nbp_switchdev_sync_objs(p, ctx, atomic_nb, blocking_nb, extack);
+}

net/switchdev/switchdev.c

···
 					  NULL);
 }
 EXPORT_SYMBOL_GPL(switchdev_bridge_port_unoffload);
+
+int switchdev_bridge_port_replay(struct net_device *brport_dev,
+				 struct net_device *dev, const void *ctx,
+				 struct notifier_block *atomic_nb,
+				 struct notifier_block *blocking_nb,
+				 struct netlink_ext_ack *extack)
+{
+	struct switchdev_notifier_brport_info brport_info = {
+		.brport = {
+			.dev = dev,
+			.ctx = ctx,
+			.atomic_nb = atomic_nb,
+			.blocking_nb = blocking_nb,
+		},
+	};
+	int err;
+
+	ASSERT_RTNL();
+
+	err = call_switchdev_blocking_notifiers(SWITCHDEV_BRPORT_REPLAY,
+						brport_dev, &brport_info.info,
+						extack);
+	return notifier_to_errno(err);
+}
+EXPORT_SYMBOL_GPL(switchdev_bridge_port_replay);