Commit bc5b1ec5 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
Browse files

n_tty: Only flush echo output if actually output 



Don't have the driver flush received echoes if no echoes were
actually output.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cbfd0340

drivers/tty/n_tty.c

+10 −8
Original line number Diff line number Diff line
@@ -646,14 +646,14 @@ static ssize_t process_output_block(struct tty_struct *tty, 
 *	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);

}