diff options
Diffstat (limited to 'drivers/char/tty_ioctl.c')
| -rw-r--r-- | drivers/char/tty_ioctl.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c index 4d540619ac8..3b6fa7b0be8 100644 --- 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; |