1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 3922a084205e..f6f0e4ec2b51 100644
--- 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;
 }