tty: Simplify tty_release_checks() interface

Passing the 'other' tty to tty_release_checks() only makes sense
for a pty pair; make o_tty scope local instead.
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_io.c

@@ -1702,8 +1702,7 @@ static void release_tty(struct tty_struct *tty, int idx)
  *	Performs some paranoid checking before true release of the @tty.
  *	This is a no-op unless TTY_PARANOIA_CHECK is defined.
  */
-static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
-		int idx)
+static int tty_release_checks(struct tty_struct *tty, int idx)
 {
 #ifdef TTY_PARANOIA_CHECK
 	if (idx < 0 || idx >= tty->driver->num) {
@@ -1722,6 +1721,8 @@ static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
 		return -1;
 	}
 	if (tty->driver->other) {
+		struct tty_struct *o_tty = tty->link;
+
 		if (o_tty != tty->driver->other->ttys[idx]) {
 			printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
 					__func__, idx, tty->name);
@@ -1777,7 +1778,7 @@ int tty_release(struct inode *inode, struct file *filp)
 	/* Review: parallel close */
 	o_tty = tty->link;
 
-	if (tty_release_checks(tty, o_tty, idx)) {
+	if (tty_release_checks(tty, idx)) {
 		tty_unlock(tty);
 		return 0;
 	}