From: Arjan van de Ven <arjan@infradead.org>

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/char/tty_io.c    |   10 +++++-----
 drivers/char/tty_ioctl.c |   17 +++++++++--------
 include/linux/tty.h      |    2 +-
 3 files changed, 15 insertions(+), 14 deletions(-)

diff -puN drivers/char/tty_io.c~tty-make-termios_sem-a-mutex drivers/char/tty_io.c
--- a/drivers/char/tty_io.c~tty-make-termios_sem-a-mutex
+++ a/drivers/char/tty_io.c
@@ -618,9 +618,9 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_strin
  
 static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
 {
-	down(&tty->termios_sem);
+	mutex_lock(&tty->termios_mutex);
 	tty->termios->c_line = num;
-	up(&tty->termios_sem);
+	mutex_unlock(&tty->termios_mutex);
 }
 
 /*
@@ -1338,9 +1338,9 @@ static void do_tty_hangup(void *data)
 	 */
 	if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
 	{
-		down(&tty->termios_sem);
+		mutex_lock(&tty->termios_mutex);
 		*tty->termios = tty->driver->init_termios;
-		up(&tty->termios_sem);
+		mutex_unlock(&tty->termios_mutex);
 	}
 	
 	/* Defer ldisc switch */
@@ -3576,7 +3576,7 @@ static void initialize_tty_struct(struct
 	tty_buffer_init(tty);
 	INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
 	init_MUTEX(&tty->buf.pty_sem);
-	init_MUTEX(&tty->termios_sem);
+	mutex_init(&tty->termios_mutex);
 	init_waitqueue_head(&tty->write_wait);
 	init_waitqueue_head(&tty->read_wait);
 	INIT_WORK(&tty->hangup_work, do_tty_hangup, tty);
diff -puN drivers/char/tty_ioctl.c~tty-make-termios_sem-a-mutex drivers/char/tty_ioctl.c
--- a/drivers/char/tty_ioctl.c~tty-make-termios_sem-a-mutex
+++ a/drivers/char/tty_ioctl.c
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/bitops.h>
+#include <linux/mutex.h>
 
 #include <asm/io.h>
 #include <asm/uaccess.h>
@@ -131,7 +132,7 @@ static void change_termios(struct tty_st
 
 	/* FIXME: we need to decide on some locking/ordering semantics
 	   for the set_termios notification eventually */
-	down(&tty->termios_sem);
+	mutex_lock(&tty->termios_mutex);
 
 	*tty->termios = *new_termios;
 	unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
@@ -176,7 +177,7 @@ static void change_termios(struct tty_st
 			(ld->set_termios)(tty, &old_termios);
 		tty_ldisc_deref(ld);
 	}
-	up(&tty->termios_sem);
+	mutex_unlock(&tty->termios_mutex);
 }
 
 /**
@@ -284,13 +285,13 @@ static int get_sgttyb(struct tty_struct 
 {
 	struct sgttyb tmp;
 
-	down(&tty->termios_sem);
+	mutex_lock(&tty->termios_mutex);
 	tmp.sg_ispeed = 0;
 	tmp.sg_ospeed = 0;
 	tmp.sg_erase = tty->termios->c_cc[VERASE];
 	tmp.sg_kill = tty->termios->c_cc[VKILL];
 	tmp.sg_flags = get_sgflags(tty);
-	up(&tty->termios_sem);
+	mutex_unlock(&tty->termios_mutex);
 	
 	return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }
@@ -345,12 +346,12 @@ static int set_sgttyb(struct tty_struct 
 	if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
 		return -EFAULT;
 
-	down(&tty->termios_sem);		
+	mutex_lock(&tty->termios_mutex);
 	termios =  *tty->termios;
 	termios.c_cc[VERASE] = tmp.sg_erase;
 	termios.c_cc[VKILL] = tmp.sg_kill;
 	set_sgflags(&termios, tmp.sg_flags);
-	up(&tty->termios_sem);
+	mutex_unlock(&tty->termios_mutex);
 	change_termios(tty, &termios);
 	return 0;
 }
@@ -592,11 +593,11 @@ int n_tty_ioctl(struct tty_struct * tty,
 		case TIOCSSOFTCAR:
 			if (get_user(arg, (unsigned int __user *) arg))
 				return -EFAULT;
-			down(&tty->termios_sem);
+			mutex_lock(&tty->termios_mutex);
 			tty->termios->c_cflag =
 				((tty->termios->c_cflag & ~CLOCAL) |
 				 (arg ? CLOCAL : 0));
-			up(&tty->termios_sem);
+			mutex_unlock(&tty->termios_mutex);
 			return 0;
 		default:
 			return -ENOIOCTLCMD;
diff -puN include/linux/tty.h~tty-make-termios_sem-a-mutex include/linux/tty.h
--- a/include/linux/tty.h~tty-make-termios_sem-a-mutex
+++ a/include/linux/tty.h
@@ -174,7 +174,7 @@ struct tty_struct {
 	struct tty_driver *driver;
 	int index;
 	struct tty_ldisc ldisc;
-	struct semaphore termios_sem;
+	struct mutex termios_mutex;
 	struct termios *termios, *termios_locked;
 	char name[64];
 	int pgrp;
_