[PATCH] tty_driver refcounting

drivers/isdn/i4l/isdn_tty.c converted to dynamic allocation

drivers/isdn/i4l/isdn_tty.c

@@ -1986,6 +1986,21 @@ modem_write_profile(atemu * m)
 		group_send_sig_info(SIGIO, SEND_SIG_PRIV, dev->profd);
 }
 
+static struct tty_operations modem_ops = {
+	.open = isdn_tty_open,
+	.close = isdn_tty_close,
+	.write = isdn_tty_write,
+	.flush_chars = isdn_tty_flush_chars,
+	.write_room = isdn_tty_write_room,
+	.chars_in_buffer = isdn_tty_chars_in_buffer,
+	.flush_buffer = isdn_tty_flush_buffer,
+	.ioctl = isdn_tty_ioctl,
+	.throttle = isdn_tty_throttle,
+	.unthrottle = isdn_tty_unthrottle,
+	.set_termios = isdn_tty_set_termios,
+	.hangup = isdn_tty_hangup,
+};
+
 int
 isdn_tty_init(void)
 {
@@ -1994,36 +2009,21 @@ isdn_tty_init(void)
 	modem_info *info;
 
 	m = &isdn_mdm;
-	memset(&m->tty_modem, 0, sizeof(struct tty_driver));
-	m->tty_modem.magic = TTY_DRIVER_MAGIC;
-	m->tty_modem.name = "ttyI";
-	m->tty_modem.devfs_name = "isdn/ttyI";
-	m->tty_modem.major = ISDN_TTY_MAJOR;
-	m->tty_modem.minor_start = 0;
-	m->tty_modem.num = ISDN_MAX_CHANNELS;
-	m->tty_modem.type = TTY_DRIVER_TYPE_SERIAL;
-	m->tty_modem.subtype = SERIAL_TYPE_NORMAL;
-	m->tty_modem.init_termios = tty_std_termios;
-	m->tty_modem.init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
-	m->tty_modem.flags = TTY_DRIVER_REAL_RAW;
-	m->tty_modem.open = isdn_tty_open;
-	m->tty_modem.close = isdn_tty_close;
-	m->tty_modem.write = isdn_tty_write;
-	m->tty_modem.put_char = NULL;
-	m->tty_modem.flush_chars = isdn_tty_flush_chars;
-	m->tty_modem.write_room = isdn_tty_write_room;
-	m->tty_modem.chars_in_buffer = isdn_tty_chars_in_buffer;
-	m->tty_modem.flush_buffer = isdn_tty_flush_buffer;
-	m->tty_modem.ioctl = isdn_tty_ioctl;
-	m->tty_modem.throttle = isdn_tty_throttle;
-	m->tty_modem.unthrottle = isdn_tty_unthrottle;
-	m->tty_modem.set_termios = isdn_tty_set_termios;
-	m->tty_modem.stop = NULL;
-	m->tty_modem.start = NULL;
-	m->tty_modem.hangup = isdn_tty_hangup;
-	m->tty_modem.driver_name = "isdn_tty";
-
-	retval = tty_register_driver(&m->tty_modem);
+	m->tty_modem = alloc_tty_driver(ISDN_MAX_CHANNELS);
+	if (!m->tty_modem)
+		return -ENOMEM;
+	m->tty_modem->name = "ttyI";
+	m->tty_modem->devfs_name = "isdn/ttyI";
+	m->tty_modem->major = ISDN_TTY_MAJOR;
+	m->tty_modem->minor_start = 0;
+	m->tty_modem->type = TTY_DRIVER_TYPE_SERIAL;
+	m->tty_modem->subtype = SERIAL_TYPE_NORMAL;
+	m->tty_modem->init_termios = tty_std_termios;
+	m->tty_modem->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	m->tty_modem->flags = TTY_DRIVER_REAL_RAW;
+	m->tty_modem->driver_name = "isdn_tty";
+	tty_set_operations(m->tty_modem, &modem_ops);
+	retval = tty_register_driver(m->tty_modem);
 	if (retval) {
 		printk(KERN_WARNING "isdn_tty: Couldn't register modem-device\n");
 		goto err;
@@ -2096,8 +2096,10 @@ isdn_tty_init(void)
 		kfree(info->xmit_buf - 4);
 	}
  err_unregister_tty:
-	tty_unregister_driver(&isdn_mdm.tty_modem);
+	tty_unregister_driver(&isdn_mdm->tty_modem);
  err:
+	put_tty_driver(&isdn_mdm->tty_modem);
+	isdn_mdm->tty_modem = NULL;
 	return retval;
 }
 
@@ -2116,7 +2118,9 @@ isdn_tty_exit(void)
 #endif
 		kfree(info->xmit_buf - 4);
 	}
-	tty_unregister_driver(&isdn_mdm.tty_modem);
+	tty_unregister_driver(&isdn_mdm->tty_modem);
+	put_tty_driver(&isdn_mdm->tty_modem);
+	isdn_mdm->tty_modem = NULL;
 }
 
 /*

drivers/isdn/i4l/isdn_tty.h

@@ -114,7 +114,7 @@ extern int isdn_tty_init(void);
 extern void isdn_tty_exit(void);
 
 struct isdn_modem {
-  struct tty_driver  tty_modem;			   /* tty-device             */
+  struct tty_driver  *tty_modem;		   /* tty-device             */
   modem_info         info[ISDN_MAX_CHANNELS];	   /* Private data           */
 };