tty: Convert termios_mutex to termios_rwsem

termios is commonly accessed unsafely (especially by N_TTY)
because the existing mutex forces exclusive access.
Convert existing usage.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/net/irda/irtty-sir.c b/drivers/net/irda/irtty-sir.c
index a41267197839..177441afeb96 100644
--- a/drivers/net/irda/irtty-sir.c
+++ b/drivers/net/irda/irtty-sir.c
@@ -123,14 +123,14 @@ static int irtty_change_speed(struct sir_dev *dev, unsigned speed)
 
         tty = priv->tty;
 
-        mutex_lock(&tty->termios_mutex);
+        down_write(&tty->termios_rwsem);
         old_termios = tty->termios;
         cflag = tty->termios.c_cflag;
         tty_encode_baud_rate(tty, speed, speed);
         if (tty->ops->set_termios)
                 tty->ops->set_termios(tty, &old_termios);
         priv->io.speed = speed;
-        mutex_unlock(&tty->termios_mutex);
+        up_write(&tty->termios_rwsem);
 
         return 0;
 }
@@ -280,7 +280,7 @@ static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
         struct ktermios old_termios;
         int cflag;
 
-        mutex_lock(&tty->termios_mutex);
+        down_write(&tty->termios_rwsem);
         old_termios = tty->termios;
         cflag = tty->termios.c_cflag;
         
@@ -292,7 +292,7 @@ static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
         tty->termios.c_cflag = cflag;
         if (tty->ops->set_termios)
                 tty->ops->set_termios(tty, &old_termios);
-        mutex_unlock(&tty->termios_mutex);
+        up_write(&tty->termios_rwsem);
 }
 
 /*****************************************************************/