[PATCH] tty_driver refcounting

drivers/char/synclink.c converted to dynamic allocation

drivers/char/synclink.c

@@ -932,7 +932,7 @@ static struct pci_driver synclink_pci_driver = {
 	.remove		= __devexit_p(synclink_remove_one),
 };
 
-static struct tty_driver serial_driver;
+static struct tty_driver *serial_driver;
 
 /* number of characters left in xmit buffer before we ask for more */
 #define WAKEUP_CHARS 256
@@ -4431,6 +4431,30 @@ struct mgsl_struct* mgsl_allocate_device()
 
 }	/* end of mgsl_allocate_device()*/
 
+static struct tty_operations mgsl_ops = {
+	.open = mgsl_open,
+	.close = mgsl_close,
+	.write = mgsl_write,
+	.put_char = mgsl_put_char,
+	.flush_chars = mgsl_flush_chars,
+	.write_room = mgsl_write_room,
+	.chars_in_buffer = mgsl_chars_in_buffer,
+	.flush_buffer = mgsl_flush_buffer,
+	.ioctl = mgsl_ioctl,
+	.throttle = mgsl_throttle,
+	.unthrottle = mgsl_unthrottle,
+	.send_xchar = mgsl_send_xchar,
+	.break_ctl = mgsl_break,
+	.wait_until_sent = mgsl_wait_until_sent,
+ 	.read_proc = mgsl_read_proc,
+	.set_termios = mgsl_set_termios,
+	.stop = mgsl_stop,
+	.start = mgsl_start,
+	.hangup = mgsl_hangup,
+	.tiocmget = tiocmget,
+	.tiocmset = tiocmset,
+};
+
 /*
  * perform tty device initialization
  */
@@ -4438,52 +4462,29 @@ int mgsl_init_tty(void);
 int mgsl_init_tty()
 {
 	struct mgsl_struct *info;
-	/* Initialize the tty_driver structure */
-	
-	memset(&serial_driver, 0, sizeof(struct tty_driver));
-	serial_driver.magic = TTY_DRIVER_MAGIC;
-	serial_driver.owner = THIS_MODULE;
-	serial_driver.driver_name = "synclink";
-	serial_driver.name = "ttySL";
-	serial_driver.major = ttymajor;
-	serial_driver.minor_start = 64;
-	serial_driver.num = mgsl_device_count;
-	serial_driver.type = TTY_DRIVER_TYPE_SERIAL;
-	serial_driver.subtype = SERIAL_TYPE_NORMAL;
-	serial_driver.init_termios = tty_std_termios;
-	serial_driver.init_termios.c_cflag =
+	serial_driver = alloc_tty_driver(mgsl_device_count);
+	if (!serial_driver)
+		return -ENOMEM;
+	
+	serial_driver->owner = THIS_MODULE;
+	serial_driver->driver_name = "synclink";
+	serial_driver->name = "ttySL";
+	serial_driver->major = ttymajor;
+	serial_driver->minor_start = 64;
+	serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
+	serial_driver->subtype = SERIAL_TYPE_NORMAL;
+	serial_driver->init_termios = tty_std_termios;
+	serial_driver->init_termios.c_cflag =
 		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
-	serial_driver.flags = TTY_DRIVER_REAL_RAW;
-
-	serial_driver.open = mgsl_open;
-	serial_driver.close = mgsl_close;
-	serial_driver.write = mgsl_write;
-	serial_driver.put_char = mgsl_put_char;
-	serial_driver.flush_chars = mgsl_flush_chars;
-	serial_driver.write_room = mgsl_write_room;
-	serial_driver.chars_in_buffer = mgsl_chars_in_buffer;
-	serial_driver.flush_buffer = mgsl_flush_buffer;
-	serial_driver.ioctl = mgsl_ioctl;
-	serial_driver.throttle = mgsl_throttle;
-	serial_driver.unthrottle = mgsl_unthrottle;
-	serial_driver.send_xchar = mgsl_send_xchar;
-	serial_driver.break_ctl = mgsl_break;
-	serial_driver.wait_until_sent = mgsl_wait_until_sent;
- 	serial_driver.read_proc = mgsl_read_proc;
-	serial_driver.set_termios = mgsl_set_termios;
-	serial_driver.stop = mgsl_stop;
-	serial_driver.start = mgsl_start;
-	serial_driver.hangup = mgsl_hangup;
-	serial_driver.tiocmget = tiocmget;
-	serial_driver.tiocmset = tiocmset;
-	
-	if (tty_register_driver(&serial_driver) < 0)
+	serial_driver->flags = TTY_DRIVER_REAL_RAW;
+	tty_set_operations(serial_driver, &mgsl_ops);
+	if (tty_register_driver(serial_driver) < 0)
 		printk("%s(%d):Couldn't register serial driver\n",
 			__FILE__,__LINE__);
 			
  	printk("%s %s, tty major#%d\n",
 		driver_name, driver_version,
-		serial_driver.major);
+		serial_driver->major);
 	return 0;
 }
 
@@ -4572,10 +4573,11 @@ static void __exit synclink_exit(void)
 
 	printk("Unloading %s: %s\n", driver_name, driver_version);
 
-	if ((rc = tty_unregister_driver(&serial_driver)))
+	if ((rc = tty_unregister_driver(serial_driver)))
 		printk("%s(%d) failed to unregister tty driver err=%d\n",
 		       __FILE__,__LINE__,rc);
 
+	put_tty_driver(serial_driver);
 	info = mgsl_device_list;
 	while(info) {
 #ifdef CONFIG_SYNCLINK_SYNCPPP