[RFC][PATCH 6/6]: /dev/tty tweak in init_dev()

[sukadev at us.ibm.com]

From: Sukadev Bhattiprolu <sukadev at us.ibm.com>
Subject: [RFC][PATCH 6/6]: /dev/tty tweak in init_dev()

When opening /dev/tty, __tty_open() finds the tty using get_current_tty().
When __tty_open() calls init_dev(), init_dev() tries to 'find' the tty
again from devpts.  Is that really necessary ?

The problem with asking devpts again is that with multiple mounts, devpts
cannot find the tty without knowing the specific mount instance. We can't
find the mount instance of devpts, since the inode of /dev/tty is in a
different filesystem.

---
 drivers/char/tty_io.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6.26-rc8-mm1/drivers/char/tty_io.c
===================================================================
--- linux-2.6.26-rc8-mm1.orig/drivers/char/tty_io.c	2008-08-04 17:25:20.000000000 -0700
+++ linux-2.6.26-rc8-mm1/drivers/char/tty_io.c	2008-08-04 17:26:34.000000000 -0700
@@ -2066,7 +2066,10 @@ static int init_dev(struct tty_driver *d
 
 	/* check whether we're reopening an existing tty */
 	if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
-		tty = devpts_get_tty(inode, idx);
+		if (inode->i_rdev == MKDEV(TTYAUX_MAJOR, 0))
+			tty = *ret_tty;
+		else
+			tty = devpts_get_tty(inode, idx);
 		/*
 		 * If we don't have a tty here on a slave open, it's because
 		 * the master already started the close process and there's