tty: N_TTY SIGIO only works for read

[deliverable/linux.git] / drivers / char / n_tty.c

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 3922a084205e088fc1d43e0bfa357fa4847d4832..f6f0e4ec2b510dde6ca5079f6def074e34f6fdce 100644 (file)
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -1352,10 +1352,8 @@ static void n_tty_write_wakeup(struct tty_struct *tty)
        /* Write out any echoed characters that are still pending */
        process_echoes(tty);
 
-       if (tty->fasync) {
-               set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+       if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
                kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
-       }
 }
 
 /**
@@ -2014,6 +2012,8 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
 break_out:
        __set_current_state(TASK_RUNNING);
        remove_wait_queue(&tty->write_wait, &wait);
+       if (b - buf != nr && tty->fasync)
+               set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
        return (b - buf) ? b - buf : retval;
 }