Don't have the driver flush received echoes if no echoes were actually output.
Signed-off-by: Peter Hurley <[email protected]> --- drivers/tty/n_tty.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 6f507f5..a601c46 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -645,14 +645,14 @@ break_out: * Locking: callers must hold output_lock */ -static void __process_echoes(struct tty_struct *tty) +static size_t __process_echoes(struct tty_struct *tty) { struct n_tty_data *ldata = tty->disc_data; - int space, nr; + int space, old_space; size_t tail; unsigned char c; - space = tty_write_room(tty); + old_space = space = tty_write_room(tty); tail = ldata->echo_tail; nr = ldata->echo_commit - ldata->echo_tail; @@ -785,12 +785,13 @@ static void __process_echoes(struct tty_struct *tty) } ldata->echo_tail = tail; + return old_space - space; } static void commit_echoes(struct tty_struct *tty) { struct n_tty_data *ldata = tty->disc_data; - size_t nr, old; + size_t nr, old, echoed; size_t head; head = ldata->echo_head; @@ -805,25 +806,26 @@ static void commit_echoes(struct tty_struct *tty) mutex_lock(&ldata->output_lock); ldata->echo_commit = head; - __process_echoes(tty); + echoed = __process_echoes(tty); mutex_unlock(&ldata->output_lock); - if (tty->ops->flush_chars) + if (echoed && tty->ops->flush_chars) tty->ops->flush_chars(tty); } static void process_echoes(struct tty_struct *tty) { struct n_tty_data *ldata = tty->disc_data; + size_t echoed; if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail) return; mutex_lock(&ldata->output_lock); - __process_echoes(tty); + echoed = __process_echoes(tty); mutex_unlock(&ldata->output_lock); - if (tty->ops->flush_chars) + if (echoed && tty->ops->flush_chars) tty->ops->flush_chars(tty); } -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
