1 files changed, 27 insertions, 6 deletions

diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 851cfcd2702a..d769e43f73fb 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -756,6 +756,32 @@ static int send_prio_char(struct tty_struct *tty, char ch)
 }
 
 /**
+ *      tty_change_softcar      -       carrier change ioctl helper
+ *      @tty: tty to update
+ *      @arg: enable/disable CLOCAL
+ *
+ *      Perform a change to the CLOCAL state and call into the driver
+ *      layer to make it visible. All done with the termios mutex
+ */
+
+static int tty_change_softcar(struct tty_struct *tty, int arg)
+{
+        int ret = 0;
+        int bit = arg ? CLOCAL : 0;
+        struct ktermios old = *tty->termios;
+
+        mutex_lock(&tty->termios_mutex);
+        tty->termios->c_cflag &= ~CLOCAL;
+        tty->termios->c_cflag |= bit;
+        if (tty->driver->set_termios)
+                tty->driver->set_termios(tty, &old);
+        if ((tty->termios->c_cflag & CLOCAL) != bit)
+                ret = -EINVAL;
+        mutex_unlock(&tty->termios_mutex);
+        return ret;
+}
+
+/**
  *      tty_mode_ioctl          -       mode related ioctls
  *      @tty: tty for the ioctl
  *      @file: file pointer for the tty
@@ -865,12 +891,7 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
         case TIOCSSOFTCAR:
                 if (get_user(arg, (unsigned int __user *) arg))
                         return -EFAULT;
-                mutex_lock(&tty->termios_mutex);
-                tty->termios->c_cflag =
-                        ((tty->termios->c_cflag & ~CLOCAL) |
-                         (arg ? CLOCAL : 0));
-                mutex_unlock(&tty->termios_mutex);
-                return 0;
+                return tty_change_softcar(tty, arg);
         default:
                 return -ENOIOCTLCMD;
         }