[patch net-next v3 2/3] net: devlink: export devlink net set/get helpers

[Jiri Pirko <jiri@resnulli.us>]

From: Jiri Pirko <jiri@mellanox.com>

Allow drivers to set/get net struct for devlink instance. Set is only
allowed for newly allocated devlink instance.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 include/net/devlink.h |  3 +++
 net/core/devlink.c    | 18 ++++++++++++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 451268f64880..c45b10d79b14 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -35,6 +35,7 @@ struct devlink {
 	struct device *dev;
 	possible_net_t _net;
 	struct mutex lock;
+	bool registered;
 	char priv[0] __aligned(NETDEV_ALIGN);
 };
 
@@ -591,6 +592,8 @@ 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);
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 6f8c1b2cdfb2..80a4b3ae9d39 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -92,16 +92,25 @@ static LIST_HEAD(devlink_list);
  */
 static DEFINE_MUTEX(devlink_mutex);
 
-static struct net *devlink_net(const struct devlink *devlink)
+struct net *devlink_net(const struct devlink *devlink)
 {
 	return read_pnet(&devlink->_net);
 }
+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)
 {
@@ -690,7 +699,7 @@ static void devlink_netns_change(struct devlink *devlink, struct net *net)
 	if (net_eq(devlink_net(devlink), net))
 		return;
 	devlink_all_del_notify(devlink);
-	devlink_net_set(devlink, net);
+	__devlink_net_set(devlink, net);
 	devlink_all_add_notify(devlink);
 }
 
@@ -5606,7 +5615,7 @@ 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);
@@ -5630,6 +5639,7 @@ 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);
-- 
2.21.0