[PATCH v3 net-next 03/10] rtnetlink: Remove __rtnl_link_register()

[Kuniyuki Iwashima <kuniyu@amazon.com>]

link_ops is protected by link_ops_mutex and no longer needs RTNL,
so we have no reason to have __rtnl_link_register() separately.

Let's remove it and call rtnl_link_register() from ifb.ko and
dummy.ko.

Note that both modules' init() work on init_net only, so we need
not export pernet_ops_rwsem and can use rtnl_net_lock() there.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 drivers/net/dummy.c      | 17 ++++++-----------
 drivers/net/ifb.c        | 17 ++++++-----------
 include/net/rtnetlink.h  |  2 --
 net/core/net_namespace.c |  1 -
 net/core/rtnetlink.c     | 35 +++++++----------------------------
 5 files changed, 19 insertions(+), 53 deletions(-)

diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
index 72618b6af44e..005d79975f3b 100644
--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -166,27 +166,22 @@ static int __init dummy_init_one(void)
 
 static int __init dummy_init_module(void)
 {
-	bool need_unregister = false;
 	int i, err = 0;
 
-	down_write(&pernet_ops_rwsem);
-	rtnl_lock();
-	err = __rtnl_link_register(&dummy_link_ops);
+	err = rtnl_link_register(&dummy_link_ops);
 	if (err < 0)
-		goto out;
+		return err;
+
+	rtnl_net_lock(&init_net);
 
 	for (i = 0; i < numdummies && !err; i++) {
 		err = dummy_init_one();
 		cond_resched();
 	}
-	if (err < 0)
-		need_unregister = true;
 
-out:
-	rtnl_unlock();
-	up_write(&pernet_ops_rwsem);
+	rtnl_net_unlock(&init_net);
 
-	if (need_unregister)
+	if (err < 0)
 		rtnl_link_unregister(&dummy_link_ops);
 
 	return err;
diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index a4b9ec4e8f30..67424888ff0a 100644
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -424,27 +424,22 @@ static int __init ifb_init_one(int index)
 
 static int __init ifb_init_module(void)
 {
-	bool need_unregister = false;
 	int i, err;
 
-	down_write(&pernet_ops_rwsem);
-	rtnl_lock();
-	err = __rtnl_link_register(&ifb_link_ops);
+	err = rtnl_link_register(&ifb_link_ops);
 	if (err < 0)
-		goto out;
+		return err;
+
+	rtnl_net_lock(&init_net);
 
 	for (i = 0; i < numifbs && !err; i++) {
 		err = ifb_init_one(i);
 		cond_resched();
 	}
-	if (err)
-		need_unregister = true;
 
-out:
-	rtnl_unlock();
-	up_write(&pernet_ops_rwsem);
+	rtnl_net_unlock(&init_net);
 
-	if (need_unregister)
+	if (err)
 		rtnl_link_unregister(&ifb_link_ops);
 
 	return err;
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 7559020f760c..ef7c11f0d74c 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -164,8 +164,6 @@ struct rtnl_link_ops {
 						   int *prividx, int attr);
 };
 
-int __rtnl_link_register(struct rtnl_link_ops *ops);
-
 int rtnl_link_register(struct rtnl_link_ops *ops);
 void rtnl_link_unregister(struct rtnl_link_ops *ops);
 
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 809b48c0a528..157021ced442 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -56,7 +56,6 @@ static bool init_net_initialized;
  * outside.
  */
 DECLARE_RWSEM(pernet_ops_rwsem);
-EXPORT_SYMBOL_GPL(pernet_ops_rwsem);
 
 #define MIN_PERNET_OPS_ID	\
 	((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index fcccb916e468..61bf710f97b8 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -495,20 +495,21 @@ static void rtnl_link_ops_put(struct rtnl_link_ops *ops, int srcu_index)
 }
 
 /**
- * __rtnl_link_register - Register rtnl_link_ops with rtnetlink.
+ * rtnl_link_register - Register rtnl_link_ops with rtnetlink.
  * @ops: struct rtnl_link_ops * to register
  *
- * The caller must hold the rtnl_mutex. This function should be used
- * by drivers that create devices during module initialization. It
- * must be called before registering the devices.
- *
  * Returns 0 on success or a negative error code.
  */
-int __rtnl_link_register(struct rtnl_link_ops *ops)
+int rtnl_link_register(struct rtnl_link_ops *ops)
 {
 	struct rtnl_link_ops *tmp;
 	int err;
 
+	/* Sanity-check max sizes to avoid stack buffer overflow. */
+	if (WARN_ON(ops->maxtype > RTNL_MAX_TYPE ||
+		    ops->slave_maxtype > RTNL_SLAVE_MAX_TYPE))
+		return -EINVAL;
+
 	/* The check for alloc/setup is here because if ops
 	 * does not have that filled up, it is not possible
 	 * to use the ops for creating device. So do not
@@ -536,28 +537,6 @@ int __rtnl_link_register(struct rtnl_link_ops *ops)
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(__rtnl_link_register);
-
-/**
- * rtnl_link_register - Register rtnl_link_ops with rtnetlink.
- * @ops: struct rtnl_link_ops * to register
- *
- * Returns 0 on success or a negative error code.
- */
-int rtnl_link_register(struct rtnl_link_ops *ops)
-{
-	int err;
-
-	/* Sanity-check max sizes to avoid stack buffer overflow. */
-	if (WARN_ON(ops->maxtype > RTNL_MAX_TYPE ||
-		    ops->slave_maxtype > RTNL_SLAVE_MAX_TYPE))
-		return -EINVAL;
-
-	rtnl_lock();
-	err = __rtnl_link_register(ops);
-	rtnl_unlock();
-	return err;
-}
 EXPORT_SYMBOL_GPL(rtnl_link_register);
 
 static void __rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops)
-- 
2.39.5 (Apple Git-154)