[RFC net-next 5/8] devlink: Add variant of devlink_register/unregister

[Parav Pandit]

Add variants of devlink_register and devlink_unregister which doesn't
explicitly acquire/release devlink_mutex lock, but requires that caller
hold the devlink_mutex lock.

This is required to create child devlink devices while working on
parent devlink device.

Change-Id: I74417158144b28ff51ecfb2d1105c83ebefdf985
Signed-off-by: Parav Pandit <parav@xxxxxxxxxxxx>
---
 include/net/devlink.h | 15 ++++++++++++++-
 net/core/devlink.c    | 36 +++++++++++++++++++++++++++++++-----
 2 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index ae5e0e6..9a067b1 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -545,7 +545,9 @@ static inline struct devlink *priv_to_devlink(void *priv)
 void devlink_init(struct devlink *devlink, const struct devlink_ops *ops);
 void devlink_cleanup(struct devlink *devlink);
 struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size);
+void __devlink_register(struct devlink *devlink, struct device *dev);
 int devlink_register(struct devlink *devlink, struct device *dev);
+void __devlink_unregister(struct devlink *devlink);
 void devlink_unregister(struct devlink *devlink);
 void devlink_free(struct devlink *devlink);
 int devlink_port_register(struct devlink *devlink,
@@ -713,6 +715,7 @@ int devlink_health_report(struct devlink_health_reporter *reporter,
 
 static inline void devlink_init(struct devlink *devlink,
 				const struct devlink_ops *ops)
+{
 }
 
 static inline void devlink_cleanup(struct devlink *devlink)
@@ -725,11 +728,21 @@ static inline struct devlink *devlink_alloc(const struct devlink_ops *ops,
 	return kzalloc(sizeof(struct devlink) + priv_size, GFP_KERNEL);
 }
 
-static inline int devlink_register(struct devlink *devlink, struct device *dev)
+static inline void __devlink_register(struct devlink *devlink,
+				      struct device *dev)
+{
+}
+
+static inline int devlink_register(struct devlink *devlink,
+				   struct device *dev)
 {
 	return 0;
 }
 
+static inline void __devlink_unregister(struct devlink *devlink)
+{
+}
+
 static inline void devlink_unregister(struct devlink *devlink)
 {
 }
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 25492c6..cfbad2c 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -5262,22 +5262,49 @@ struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size)
 EXPORT_SYMBOL_GPL(devlink_alloc);
 
 /**
- *	devlink_register - Register devlink instance
+ *	__devlink_register - Register devlink instance
+ *	Caller must hold devlink_mutex.
  *
  *	@devlink: devlink
  */
-int devlink_register(struct devlink *devlink, struct device *dev)
+void __devlink_register(struct devlink *devlink, struct device *dev)
 {
-	mutex_lock(&devlink_mutex);
+	lockdep_assert_held(&devlink_mutex);
 	devlink->dev = dev;
 	list_add_tail(&devlink->list, &devlink_list);
 	devlink_notify(devlink, DEVLINK_CMD_NEW);
+}
+EXPORT_SYMBOL_GPL(__devlink_register);
+
+/**
+ *	devlink_register - Register devlink instance
+ *
+ *	@devlink: devlink
+ */
+int devlink_register(struct devlink *devlink, struct device *dev)
+{
+	mutex_lock(&devlink_mutex);
+	__devlink_register(devlink, dev);
 	mutex_unlock(&devlink_mutex);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(devlink_register);
 
 /**
+ *	__devlink_unregister - Unregister devlink instance
+ *	Caller must hold the devlink_mutex while invoking this API.
+ *
+ *	@devlink: devlink
+ */
+void __devlink_unregister(struct devlink *devlink)
+{
+	lockdep_assert_held(&devlink_mutex);
+	devlink_notify(devlink, DEVLINK_CMD_DEL);
+	list_del(&devlink->list);
+}
+EXPORT_SYMBOL_GPL(__devlink_unregister);
+
+/**
  *	devlink_unregister - Unregister devlink instance
  *
  *	@devlink: devlink
@@ -5285,8 +5312,7 @@ int devlink_register(struct devlink *devlink, struct device *dev)
 void devlink_unregister(struct devlink *devlink)
 {
 	mutex_lock(&devlink_mutex);
-	devlink_notify(devlink, DEVLINK_CMD_DEL);
-	list_del(&devlink->list);
+	__devlink_unregister(devlink);
 	mutex_unlock(&devlink_mutex);
 }
 EXPORT_SYMBOL_GPL(devlink_unregister);
-- 
1.8.3.1