Merge branch 'upstream-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/linvil...

[linux-2.6-omap-h63xx.git] / drivers / char / tty_ioctl.c

diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 4d540619ac843ded9b54915fe036ad32ab7c63c9..3b6fa7b0be8ba81c1f9d658cf63740394225172d 100644 (file)
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -423,24 +423,28 @@ static int set_ltchars(struct tty_struct * tty, struct ltchars __user * ltchars)
  *
  *     Send a high priority character to the tty even if stopped
  *
- *     Locking: none
- *
- *     FIXME: overlapping calls with start/stop tty lose state of tty
+ *     Locking: none for xchar method, write ordering for write method.
  */
 
-static void send_prio_char(struct tty_struct *tty, char ch)
+static int send_prio_char(struct tty_struct *tty, char ch)
 {
        int     was_stopped = tty->stopped;
 
        if (tty->driver->send_xchar) {
                tty->driver->send_xchar(tty, ch);
-               return;
+               return 0;
        }
+
+       if (mutex_lock_interruptible(&tty->atomic_write_lock))
+               return -ERESTARTSYS;
+
        if (was_stopped)
                start_tty(tty);
        tty->driver->write(tty, &ch, 1);
        if (was_stopped)
                stop_tty(tty);
+       mutex_unlock(&tty->atomic_write_lock);
+       return 0;
 }
 
 int n_tty_ioctl(struct tty_struct * tty, struct file * file,
@@ -514,11 +518,11 @@ int n_tty_ioctl(struct tty_struct * tty, struct file * file,
                                break;
                        case TCIOFF:
                                if (STOP_CHAR(tty) != __DISABLED_CHAR)
-                                       send_prio_char(tty, STOP_CHAR(tty));
+                                       return send_prio_char(tty, STOP_CHAR(tty));
                                break;
                        case TCION:
                                if (START_CHAR(tty) != __DISABLED_CHAR)
-                                       send_prio_char(tty, START_CHAR(tty));
+                                       return send_prio_char(tty, START_CHAR(tty));
                                break;
                        default:
                                return -EINVAL;