[PATCH] tty_driver refcounting

drivers/tc/zs.c converted to dynamic allocation

drivers/tc/zs.c

@@ -180,7 +180,7 @@ static unsigned char zs_init_regs[16] __initdata = {
 
 DECLARE_TASK_QUEUE(tq_zs_serial);
 
-struct tty_driver serial_driver;
+static struct tty_driver *serial_driver;
 
 /* serial subtype definitions */
 #define SERIAL_TYPE_NORMAL	1
@@ -1800,6 +1800,25 @@ static void __init probe_sccs(void)
 	restore_flags(flags); */
 }
 
+static struct tty_operations serial_ops = {
+	.open = rs_open,
+	.close = rs_close,
+	.write = rs_write,
+	.flush_chars = rs_flush_chars,
+	.write_room = rs_write_room,
+	.chars_in_buffer = rs_chars_in_buffer,
+	.flush_buffer = rs_flush_buffer,
+	.ioctl = rs_ioctl,
+	.throttle = rs_throttle,
+	.unthrottle = rs_unthrottle,
+	.set_termios = rs_set_termios,
+	.stop = rs_stop,
+	.start = rs_start,
+	.hangup = rs_hangup,
+	.break_ctl = rs_break,
+	.wait_until_sent = rs_wait_until_sent,
+};
+
 /* zs_init inits the driver */
 int __init zs_init(void)
 {
@@ -1817,45 +1836,29 @@ int __init zs_init(void)
 	if (zs_chain == 0)
 		probe_sccs();
 
+	serial_driver = alloc_tty_driver(zs_channels_found);
+	if (!serial_driver)
+		return -ENOMEM;
+
 	show_serial_version();
 
 	/* Initialize the tty_driver structure */
 	/* Not all of this is exactly right for us. */
 
-	memset(&serial_driver, 0, sizeof(struct tty_driver));
-	serial_driver.magic = TTY_DRIVER_MAGIC;
-	serial_driver.owner = THIS_MODULE;
-	serial_driver.devfs_name = "tts/";
-	serial_driver.name = "ttyS";
-	serial_driver.major = TTY_MAJOR;
-	serial_driver.minor_start = 64;
-	serial_driver.num = zs_channels_found;
-	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->owner = THIS_MODULE;
+	serial_driver->devfs_name = "tts/";
+	serial_driver->name = "ttyS";
+	serial_driver->major = TTY_MAJOR;
+	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 | TTY_DRIVER_NO_DEVFS;
-
-	serial_driver.open = rs_open;
-	serial_driver.close = rs_close;
-	serial_driver.write = rs_write;
-	serial_driver.flush_chars = rs_flush_chars;
-	serial_driver.write_room = rs_write_room;
-	serial_driver.chars_in_buffer = rs_chars_in_buffer;
-	serial_driver.flush_buffer = rs_flush_buffer;
-	serial_driver.ioctl = rs_ioctl;
-	serial_driver.throttle = rs_throttle;
-	serial_driver.unthrottle = rs_unthrottle;
-	serial_driver.set_termios = rs_set_termios;
-	serial_driver.stop = rs_stop;
-	serial_driver.start = rs_start;
-	serial_driver.hangup = rs_hangup;
-	serial_driver.break_ctl = rs_break;
-	serial_driver.wait_until_sent = rs_wait_until_sent;
-
-	if (tty_register_driver(&serial_driver))
+	serial_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
+	tty_set_operations(serial_driver, &serial_ops);
+
+	if (tty_register_driver(serial_driver))
 		panic("Couldn't register serial driver\n");
 
 	save_flags(flags); cli();
@@ -1899,7 +1902,7 @@ int __init zs_init(void)
 		printk("ttyS%02d at 0x%08x (irq = %d)", info->line, 
 		       info->port, info->irq);
 		printk(" is a Z85C30 SCC\n");
-		tty_register_device(&serial_driver, info->line, NULL);
+		tty_register_device(serial_driver, info->line, NULL);
 	}
 
 	restore_flags(flags);
@@ -2051,7 +2054,7 @@ static void serial_console_write(struct console *co, const char *s,
 static struct tty_driver *serial_console_device(struct console *c, int *index)
 {
 	*index = c->index;
-	return &serial_driver;
+	return serial_driver;
 }
 
 /*