Add an instance parameter devpts interfaces

Pass-in 'inode' or 'tty' parameter to devpts interfaces.  With multiple
devpts instances, these parameters will be used in subsequent patches
to identify the instance of devpts mounted. The parameters also help
simplify devpts implementation.

Changelog[v3]:
	- minor changes due to merge with ttydev updates
	- rename parameters to emphasize they are ptmx or pts inodes
	- pass-in tty_struct * to devpts_pty_kill() (this will help
	  cleanup the get_node() call in a subsequent patch)

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 005d06a..78416b9 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -225,7 +225,8 @@
 struct tty_driver;
 
 struct tty_operations {
-	struct tty_struct * (*lookup)(struct tty_driver *driver, int idx);
+	struct tty_struct * (*lookup)(struct tty_driver *driver,
+			struct inode *inode, int idx);
 	int  (*install)(struct tty_driver *driver, struct tty_struct *tty);
 	void (*remove)(struct tty_driver *driver, struct tty_struct *tty);
 	int  (*open)(struct tty_struct * tty, struct file * filp);