o net: improve the current module infrastructure

As per discussions in netdev we'll probably be moving to a brand new scheme, but this
set of changesets have been discussed and are an improvement to the current situation
and were already done prior to this thread happening.

2 files changed, 22 insertions, 7 deletions

diff --git a/include/linux/net.h b/include/linux/net.h
index 8b012430f49d..04bd681473db 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -89,9 +89,11 @@ struct page;
 struct kiocb;
 struct sockaddr;
 struct msghdr;
+struct module;
 
 struct proto_ops {
 	int		family;
+	struct module	*owner;
 	int		(*release)   (struct socket *sock);
 	int		(*bind)	     (struct socket *sock,
 				      struct sockaddr *umyaddr,
@@ -127,8 +129,6 @@ struct proto_ops {
 				      int offset, size_t size, int flags);
 };
 
-struct module;
-
 struct net_proto_family {
 	int		family;
 	int		(*create)(struct socket *sock, int protocol);
@@ -140,9 +140,6 @@ struct net_proto_family {
 	struct module	*owner;
 };
 
-extern int	     net_family_get(int family);
-extern void	     net_family_put(int family);
-
 struct iovec;
 
 extern int	     sock_wake_async(struct socket *sk, int how, int band);
@@ -227,7 +224,7 @@ SOCKCALL_WRAP(name, mmap, (struct file *file, struct socket *sock, struct vm_are
 	      \
 static struct proto_ops name##_ops = {			\
 	.family		= fam,				\
-							\
+	.owner		= THIS_MODULE,			\
 	.release	= __lock_##name##_release,	\
 	.bind		= __lock_##name##_bind,		\
 	.connect	= __lock_##name##_connect,	\
diff --git a/include/net/sock.h b/include/net/sock.h
index 4f5b79f30880..53639300bc3c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -43,7 +43,7 @@
 #include <linux/config.h>
 #include <linux/timer.h>
 #include <linux/cache.h>
-
+#include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>	/* struct sk_buff */
 #include <linux/security.h>
@@ -197,6 +197,7 @@ struct sock {
 	void			*user_data;
   
 	/* Callbacks */
+	struct module		*owner;
 	void			(*state_change)(struct sock *sk);
 	void			(*data_ready)(struct sock *sk,int bytes);
 	void			(*write_space)(struct sock *sk);
@@ -270,6 +271,23 @@ struct proto {
 	} stats[NR_CPUS];
 };
 
+static __inline__ void sk_set_owner(struct sock *sk, struct module *owner)
+{
+	/*
+	 * One should use sk_set_owner just once, after struct sock creation,
+	 * be it shortly after sk_alloc or after a function that returns a new
+	 * struct sock (and that down the call chain called sk_alloc), e.g. the
+	 * IPv4 and IPv6 modules share tcp_create_openreq_child, so if
+	 * tcp_create_openreq_child called sk_set_owner IPv6 would have to
+	 * change the ownership of this struct sock, with one not needed
+	 * transient sk_set_owner call.
+	 */
+	if (unlikely(sk->owner != NULL))
+		BUG();
+	sk->owner = owner;
+	__module_get(owner);
+}
+
 /* Called with local bh disabled */
 static __inline__ void sock_prot_inc_use(struct proto *prot)
 {