Commit 7879a9f9 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
Browse files

n_tty: Buffer work should not reschedule itself 



Although the driver-side input path must update the available
buffer space, it should not reschedule itself. If space is still
available and the flip buffers are not empty, flush_to_ldisc()
will loop again.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b8483052

drivers/tty/n_tty.c

+9 −4
Original line number Diff line number Diff line
@@ -118,14 +118,14 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x, 
 *	n_tty_set_room	-	receive space

 *	@tty: terminal

 *

 *	Sets tty->receive_room to reflect the currently available space

 *	Updates tty->receive_room to reflect the currently available space

 *	in the input buffer, and re-schedules the flip buffer work if space

 *	just became available.

 *

 *	Locks: Concurrent update is protected with read_lock

 */



static void n_tty_set_room(struct tty_struct *tty)

static int set_room(struct tty_struct *tty)

{

	struct n_tty_data *ldata = tty->disc_data;

	int left;
@@ -155,8 +155,13 @@ static void n_tty_set_room(struct tty_struct *tty) 


	raw_spin_unlock_irqrestore(&ldata->read_lock, flags);



	return left && !old_left;

}



static void n_tty_set_room(struct tty_struct *tty)

{

	/* Did this open up the receive buffer? We may need to flip */

	if (left && !old_left) {

	if (set_room(tty)) {

		WARN_RATELIMIT(tty->port->itty == NULL,

				"scheduling with invalid itty\n");

		/* see if ldisc has been killed - if so, this means that
@@ -1459,7 +1464,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, 
			tty->ops->flush_chars(tty);

	}



	n_tty_set_room(tty);

	set_room(tty);



	if ((!ldata->icanon && (ldata->read_cnt >= ldata->minimum_to_wake)) ||

		L_EXTPROC(tty)) {

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