bluetooth: rfcomm_init bug fix

rfcomm tty may be used before rfcomm_tty_driver initilized,
The problem is that now socket layer init before tty layer, if userspace
program do socket callback right here then oops will happen.

reporting in:
http://marc.info/?l=linux-bluetooth&m=124404919324542&w=2

make 3 changes:
1. remove #ifdef in rfcomm/core.c,
make it blank function when rfcomm tty not selected in rfcomm.h

2. tune the rfcomm_init error patch to ensure
tty driver initilized before rfcomm socket usage.

3. remove __exit for rfcomm_cleanup_sockets
because above change need call it in a __init function.
Reported-by: NOliver Hartkopp <oliver@hartkopp.net>
Tested-by: NOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: NDave Young <hidave.darkstar@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/bluetooth/rfcomm.h

@@ -355,7 +355,17 @@ struct rfcomm_dev_list_req {
 };
 
 int  rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
+
+#ifdef CONFIG_BT_RFCOMM_TTY
 int  rfcomm_init_ttys(void);
 void rfcomm_cleanup_ttys(void);
-
+#else
+static inline int rfcomm_init_ttys(void)
+{
+	return 0;
+}
+static inline void rfcomm_cleanup_ttys(void)
+{
+}
+#endif
 #endif /* __RFCOMM_H */

net/bluetooth/rfcomm/core.c

@@ -2080,28 +2080,41 @@ static CLASS_ATTR(rfcomm_dlc, S_IRUGO, rfcomm_dlc_sysfs_show, NULL);
 /* ---- Initialization ---- */
 static int __init rfcomm_init(void)
 {
+	int ret;
+
 	l2cap_load();
 
 	hci_register_cb(&rfcomm_cb);
 
 	rfcomm_thread = kthread_run(rfcomm_run, NULL, "krfcommd");
 	if (IS_ERR(rfcomm_thread)) {
-		hci_unregister_cb(&rfcomm_cb);
-		return PTR_ERR(rfcomm_thread);
+		ret = PTR_ERR(rfcomm_thread);
+		goto out_thread;
 	}
 
 	if (class_create_file(bt_class, &class_attr_rfcomm_dlc) < 0)
 		BT_ERR("Failed to create RFCOMM info file");
 
-	rfcomm_init_sockets();
+	ret = rfcomm_init_ttys();
+	if (ret)
+		goto out_tty;
 
-#ifdef CONFIG_BT_RFCOMM_TTY
-	rfcomm_init_ttys();
-#endif
+	ret = rfcomm_init_sockets();
+	if (ret)
+		goto out_sock;
 
 	BT_INFO("RFCOMM ver %s", VERSION);
 
 	return 0;
+
+out_sock:
+	rfcomm_cleanup_ttys();
+out_tty:
+	kthread_stop(rfcomm_thread);
+out_thread:
+	hci_unregister_cb(&rfcomm_cb);
+
+	return ret;
 }
 
 static void __exit rfcomm_exit(void)
@@ -2112,9 +2125,7 @@ static void __exit rfcomm_exit(void)
 
 	kthread_stop(rfcomm_thread);
 
-#ifdef CONFIG_BT_RFCOMM_TTY
 	rfcomm_cleanup_ttys();
-#endif
 
 	rfcomm_cleanup_sockets();
 }

net/bluetooth/rfcomm/sock.c

@@ -1132,7 +1132,7 @@ int __init rfcomm_init_sockets(void)
 	return err;
 }
 
-void __exit rfcomm_cleanup_sockets(void)
+void rfcomm_cleanup_sockets(void)
 {
 	class_remove_file(bt_class, &class_attr_rfcomm);