[PATCH] tty_driver refcounting

drivers/char/serial167.c converted to dynamic allocation

drivers/char/serial167.c

@@ -100,7 +100,7 @@
 
 DECLARE_TASK_QUEUE(tq_cyclades);
 
-struct tty_driver cy_serial_driver;
+static struct tty_driver *cy_serial_driver;
 extern int serial_console;
 static struct cyclades_port *serial_console_info = NULL;
 static unsigned int serial_console_cflag = 0;
@@ -2288,6 +2288,23 @@ mvme167_serial_console_setup(int cflag)
 					rcor >> 5, rbpr);
 } /* serial_console_init */
 
+static struct tty_operations cy_ops = {
+	.open = cy_open,
+	.close = cy_close,
+	.write = cy_write,
+	.put_char = cy_put_char,
+	.flush_chars = cy_flush_chars,
+	.write_room = cy_write_room,
+	.chars_in_buffer = cy_chars_in_buffer,
+	.flush_buffer = cy_flush_buffer,
+	.ioctl = cy_ioctl,
+	.throttle = cy_throttle,
+	.unthrottle = cy_unthrottle,
+	.set_termios = cy_set_termios,
+	.stop = cy_stop,
+	.start = cy_start,
+	.hangup = cy_hangup,
+};
 /* The serial driver boot-time initialization code!
     Hardware I/O ports are mapped to character special devices on a
     first found, first allocated manner.  That is, this code searches
@@ -2320,6 +2337,10 @@ serial167_init(void)
     if (!(mvme16x_config &MVME16x_CONFIG_GOT_CD2401))
 	return 0;
 
+    cy_serial_driver = alloc_tty_driver(NR_PORTS);
+    if (!cy_serial_driver)
+	return -ENOMEM;
+
 #if 0
 scrn[1] = '\0';
 #endif
@@ -2340,39 +2361,23 @@ scrn[1] = '\0';
 
     /* Initialize the tty_driver structure */
     
-    memset(&cy_serial_driver, 0, sizeof(struct tty_driver));
-    cy_serial_driver.magic = TTY_DRIVER_MAGIC;
-    cy_serial_driver.owner = THIS_MODULE;
-    cy_serial_driver.devfs_name = "tts/";
-    cy_serial_driver.name = "ttyS";
-    cy_serial_driver.major = TTY_MAJOR;
-    cy_serial_driver.minor_start = 64;
-    cy_serial_driver.num = NR_PORTS;
-    cy_serial_driver.type = TTY_DRIVER_TYPE_SERIAL;
-    cy_serial_driver.subtype = SERIAL_TYPE_NORMAL;
-    cy_serial_driver.init_termios = tty_std_termios;
-    cy_serial_driver.init_termios.c_cflag =
+    cy_serial_driver->owner = THIS_MODULE;
+    cy_serial_driver->devfs_name = "tts/";
+    cy_serial_driver->name = "ttyS";
+    cy_serial_driver->major = TTY_MAJOR;
+    cy_serial_driver->minor_start = 64;
+    cy_serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
+    cy_serial_driver->subtype = SERIAL_TYPE_NORMAL;
+    cy_serial_driver->init_termios = tty_std_termios;
+    cy_serial_driver->init_termios.c_cflag =
 	    B9600 | CS8 | CREAD | HUPCL | CLOCAL;
-    cy_serial_driver.flags = TTY_DRIVER_REAL_RAW;
-    cy_serial_driver.open = cy_open;
-    cy_serial_driver.close = cy_close;
-    cy_serial_driver.write = cy_write;
-    cy_serial_driver.put_char = cy_put_char;
-    cy_serial_driver.flush_chars = cy_flush_chars;
-    cy_serial_driver.write_room = cy_write_room;
-    cy_serial_driver.chars_in_buffer = cy_chars_in_buffer;
-    cy_serial_driver.flush_buffer = cy_flush_buffer;
-    cy_serial_driver.ioctl = cy_ioctl;
-    cy_serial_driver.throttle = cy_throttle;
-    cy_serial_driver.unthrottle = cy_unthrottle;
-    cy_serial_driver.set_termios = cy_set_termios;
-    cy_serial_driver.stop = cy_stop;
-    cy_serial_driver.start = cy_start;
-    cy_serial_driver.hangup = cy_hangup;
-
-    ret = tty_register_driver(&cy_serial_driver);
+    cy_serial_driver->flags = TTY_DRIVER_REAL_RAW;
+    tty_set_operations(cy_serial_driver, &cy_ops);
+
+    ret = tty_register_driver(cy_serial_driver);
     if (ret) {
 	    printk(KERN_ERR "Couldn't register MVME166/7 serial driver\n");
+	    put_tty_driver(cy_serial_driver);
 	    return ret;
     }
 
@@ -2486,8 +2491,9 @@ scrn[1] = '\0';
 cleanup_irq_cd2401_errors:
     free_irq(MVME167_IRQ_SER_ERR, cd2401_rxerr_interrupt);
 cleanup_serial_driver:
-    if (tty_unregister_driver(&cy_serial_driver))
+    if (tty_unregister_driver(cy_serial_driver))
 	    printk(KERN_ERR "Couldn't unregister MVME166/7 serial driver\n");
+    put_tty_driver(cy_serial_driver);
     return ret;
 } /* serial167_init */
 
@@ -2735,7 +2741,7 @@ void serial167_console_write(struct console *co, const char *str, unsigned count
 static struct tty_driver *serial167_console_device(struct console *c, int *index)
 {
 	*index = c->index;
-	return &cy_serial_driver;
+	return cy_serial_driver;
 }