diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 3566129..b086779 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -45,8 +45,16 @@
  *
  * void (*shutdown)(struct tty_struct * tty);
  *
- * 	This routine is called when a particular tty device is closed for
- *	the last time freeing up the resources.
+ * 	This routine is called synchronously when a particular tty device
+ *	is closed for the last time freeing up the resources.
+ *
+ *
+ * void (*cleanup)(struct tty_struct * tty);
+ *
+ *	This routine is called asynchronously when a particular tty device
+ *	is closed for the last time freeing up the resources. This is
+ *	actually the second part of shutdown for routines that might sleep.
+ *
  *
  * int (*write)(struct tty_struct * tty,
  * 		 const unsigned char *buf, int count);
@@ -233,6 +241,7 @@
 	int  (*open)(struct tty_struct * tty, struct file * filp);
 	void (*close)(struct tty_struct * tty, struct file * filp);
 	void (*shutdown)(struct tty_struct *tty);
+	void (*cleanup)(struct tty_struct *tty);
 	int  (*write)(struct tty_struct * tty,
 		      const unsigned char *buf, int count);
 	int  (*put_char)(struct tty_struct *tty, unsigned char ch);