diff options
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index c249ff1d51ce..2f6f9b5e4891 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1023,14 +1023,14 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count, return i; } -void tty_write_unlock(struct tty_struct *tty) +static void tty_write_unlock(struct tty_struct *tty) __releases(&tty->atomic_write_lock) { mutex_unlock(&tty->atomic_write_lock); wake_up_interruptible_poll(&tty->write_wait, POLLOUT); } -int tty_write_lock(struct tty_struct *tty, int ndelay) +static int tty_write_lock(struct tty_struct *tty, int ndelay) __acquires(&tty->atomic_write_lock) { if (!mutex_trylock(&tty->atomic_write_lock)) { @@ -1217,6 +1217,35 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf, return tty_write(file, buf, count, ppos); } +/** + * tty_send_xchar - send priority character + * + * Send a high priority character to the tty even if stopped + * + * Locking: none for xchar method, write ordering for write method. + */ + +int tty_send_xchar(struct tty_struct *tty, char ch) +{ + int was_stopped = tty->stopped; + + if (tty->ops->send_xchar) { + tty->ops->send_xchar(tty, ch); + return 0; + } + + if (tty_write_lock(tty, 0) < 0) + return -ERESTARTSYS; + + if (was_stopped) + start_tty(tty); + tty->ops->write(tty, &ch, 1); + if (was_stopped) + stop_tty(tty); + tty_write_unlock(tty); + return 0; +} + static char ptychar[] = "pqrstuvwxyzabcde"; /** |