n_tty: Simplify throttle threshold calculation

The adjustments performed by receive_room() are to ensure a line
termination can always be written to the read buffer. However,
these adjustments are irrelevant to the throttle threshold (because
the threshold < buffer limit).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index d4b14c30794e..7efabc4673b6 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -262,7 +262,7 @@ static void n_tty_check_throttle(struct tty_struct *tty)
         while (1) {
                 int throttled;
                 tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
-                if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE)
+                if (N_TTY_BUF_SIZE - read_cnt(ldata) >= TTY_THRESHOLD_THROTTLE)
                         break;
                 throttled = tty_throttle_safe(tty);
                 if (!throttled)