diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 5ae661c..fad365a 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2361,7 +2361,7 @@
 	}
 break_out:
 	remove_wait_queue(&tty->write_wait, &wait);
-	if (b - buf != nr && tty->fasync)
+	if (nr && tty->fasync)
 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 	up_read(&tty->termios_rwsem);
 	return (b - buf) ? b - buf : retval;