tty: Add a full port_close function

Now we are extracting out methods for shutdown and the like we can add a
proper tty_port_close method that knows all the innards of the tty closing
process and hides the lot from the caller.

At some point in the future this will be paired with a similar open()
helper and the drivers can stick to hardware management.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/tty.h b/include/linux/tty.h
index a916a31..ecb3d1b 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -187,7 +187,12 @@
 struct tty_port_operations {
 	/* Return 1 if the carrier is raised */
 	int (*carrier_raised)(struct tty_port *port);
+	/* Control the DTR line */
 	void (*dtr_rts)(struct tty_port *port, int raise);
+	/* Called when the last close completes or a hangup finishes
+	   IFF the port was initialized. Do not use to free resources */
+	void (*shutdown)(struct tty_port *port);
+	void (*drop)(struct tty_port *port);
 };
 	
 struct tty_port {
@@ -459,7 +464,8 @@
 extern int tty_port_close_start(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp);
 extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
-
+extern void tty_port_close(struct tty_port *port,
+				struct tty_struct *tty, struct file *filp);
 extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
 extern int tty_unregister_ldisc(int disc);
 extern int tty_set_ldisc(struct tty_struct *tty, int ldisc);