net: devlink: export devlink net setter

For newly allocated devlink instance allow drivers to set net struct
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/devlink.h

@@ -39,6 +39,7 @@ struct devlink {
 	possible_net_t _net;
 	struct mutex lock;
 	bool reload_failed;
+	bool registered;
 	char priv[0] __aligned(NETDEV_ALIGN);
 };
 
@@ -772,6 +773,7 @@ static inline struct devlink *netdev_to_devlink(struct net_device *dev)
 struct ib_device;
 
 struct net *devlink_net(const struct devlink *devlink);
+void devlink_net_set(struct devlink *devlink, struct net *net);
 struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size);
 int devlink_register(struct devlink *devlink, struct device *dev);
 void devlink_unregister(struct devlink *devlink);

net/core/devlink.c

@@ -101,11 +101,19 @@ struct net *devlink_net(const struct devlink *devlink)
 }
 EXPORT_SYMBOL_GPL(devlink_net);
 
-static void devlink_net_set(struct devlink *devlink, struct net *net)
+static void __devlink_net_set(struct devlink *devlink, struct net *net)
 {
 	write_pnet(&devlink->_net, net);
 }
 
+void devlink_net_set(struct devlink *devlink, struct net *net)
+{
+	if (WARN_ON(devlink->registered))
+		return;
+	__devlink_net_set(devlink, net);
+}
+EXPORT_SYMBOL_GPL(devlink_net_set);
+
 static struct devlink *devlink_get_from_attrs(struct net *net,
 					      struct nlattr **attrs)
 {
@@ -2750,7 +2758,7 @@ static void devlink_reload_netns_change(struct devlink *devlink,
 				     DEVLINK_CMD_PARAM_DEL);
 	devlink_notify(devlink, DEVLINK_CMD_DEL);
 
-	devlink_net_set(devlink, dest_net);
+	__devlink_net_set(devlink, dest_net);
 
 	devlink_notify(devlink, DEVLINK_CMD_NEW);
 	list_for_each_entry(param_item, &devlink->param_list, list)
@@ -6278,7 +6286,7 @@ struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size)
 	if (!devlink)
 		return NULL;
 	devlink->ops = ops;
-	devlink_net_set(devlink, &init_net);
+	__devlink_net_set(devlink, &init_net);
 	INIT_LIST_HEAD(&devlink->port_list);
 	INIT_LIST_HEAD(&devlink->sb_list);
 	INIT_LIST_HEAD_RCU(&devlink->dpipe_table_list);
@@ -6304,6 +6312,7 @@ int devlink_register(struct devlink *devlink, struct device *dev)
 {
 	mutex_lock(&devlink_mutex);
 	devlink->dev = dev;
+	devlink->registered = true;
 	list_add_tail(&devlink->list, &devlink_list);
 	devlink_notify(devlink, DEVLINK_CMD_NEW);
 	mutex_unlock(&devlink_mutex);