[PATCH] Revert "tty: Push the lock down further into the ldisc code"

[Ingo Molnar]

This reverts commit f18f9498e90327b9b0e245e191029e6e1996d203.

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index c408c81..1e24130 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1347,7 +1347,9 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
 	 * If we fail here just call release_tty to clean up.  No need
 	 * to decrement the use counts, as release_tty doesn't care.
 	 */
+	lock_kernel();
 	retval = tty_ldisc_setup(tty, tty->link);
+	unlock_kernel();
 	if (retval)
 		goto release_mem_out;
 	return tty;
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index 3f653f7..d914e77 100644
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -445,14 +445,8 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
 static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
 {
 	WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));
-	if (ld->ops->open) {
-		int ret;
-                /* BKL here locks verus a hangup event */
-		lock_kernel();
-		ret = ld->ops->open(tty);
-		unlock_kernel();
-		return ret;
-	}
+	if (ld->ops->open)
+		return ld->ops->open(tty);
 	return 0;
 }
 
@@ -572,7 +566,6 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 		return 0;
 	}
 
-	unlock_kernel();
 	/*
 	 *	Problem: What do we do if this blocks ?
 	 *	We could deadlock here
@@ -580,6 +573,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 
 	tty_wait_until_sent(tty, 0);
 
+	unlock_kernel();
 	mutex_lock(&tty->ldisc_mutex);
 
 	/*