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Commit 7ffb6da9 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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tty: Simplify tty_release() state checks 



The local o_tty variable in tty_release() is now accessed only
when closing the pty master.

Set o_tty to slave pty when closing pty master, otherwise NULL;
use o_tty != NULL as replacement for pty_master.

Reviewed-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 359b9fb5

drivers/tty/tty_io.c

+9 −10
Original line number Original line Diff line number Diff line
@@ -1759,8 +1759,8 @@ static int tty_release_checks(struct tty_struct *tty, int idx) 
int tty_release(struct inode *inode, struct file *filp)

int tty_release(struct inode *inode, struct file *filp)

{

{

	struct tty_struct *tty = file_tty(filp);

	struct tty_struct *tty = file_tty(filp);

	struct tty_struct *o_tty;

	struct tty_struct *o_tty = NULL;

	int	pty_master, do_sleep, final;

	int	do_sleep, final;

	int	idx;

	int	idx;

	char	buf[64];

	char	buf[64];
@@ -1773,9 +1773,8 @@ int tty_release(struct inode *inode, struct file *filp) 
	__tty_fasync(-1, filp, 0);

	__tty_fasync(-1, filp, 0);





	idx = tty->index;

	idx = tty->index;

	pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&

	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&

		      tty->driver->subtype == PTY_TYPE_MASTER);

	    tty->driver->subtype == PTY_TYPE_MASTER)

	/* Review: parallel close */

		o_tty = tty->link;

		o_tty = tty->link;





	if (tty_release_checks(tty, idx)) {

	if (tty_release_checks(tty, idx)) {
@@ -1820,7 +1819,7 @@ int tty_release(struct inode *inode, struct file *filp) 
				do_sleep++;

				do_sleep++;

			}

			}

		}

		}

		if (pty_master && o_tty->count <= 1) {

		if (o_tty && o_tty->count <= 1) {

			if (waitqueue_active(&o_tty->read_wait)) {

			if (waitqueue_active(&o_tty->read_wait)) {

				wake_up_poll(&o_tty->read_wait, POLLIN);

				wake_up_poll(&o_tty->read_wait, POLLIN);

				do_sleep++;

				do_sleep++;
@@ -1838,7 +1837,7 @@ int tty_release(struct inode *inode, struct file *filp) 
		schedule();

		schedule();

	}

	}





	if (pty_master) {

	if (o_tty) {

		if (--o_tty->count < 0) {

		if (--o_tty->count < 0) {

			printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",

			printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",

				__func__, o_tty->count, tty_name(o_tty, buf));

				__func__, o_tty->count, tty_name(o_tty, buf));
@@ -1872,13 +1871,13 @@ int tty_release(struct inode *inode, struct file *filp) 
	if (!tty->count) {

	if (!tty->count) {

		read_lock(&tasklist_lock);

		read_lock(&tasklist_lock);

		session_clear_tty(tty->session);

		session_clear_tty(tty->session);

		if (pty_master)

		if (o_tty)

			session_clear_tty(o_tty->session);

			session_clear_tty(o_tty->session);

		read_unlock(&tasklist_lock);

		read_unlock(&tasklist_lock);

	}

	}





	/* check whether both sides are closing ... */

	/* check whether both sides are closing ... */

	final = !tty->count && !(pty_master && o_tty->count);

	final = !tty->count && !(o_tty && o_tty->count);





	tty_unlock_pair(tty, o_tty);

	tty_unlock_pair(tty, o_tty);

	/* At this point, the tty->count == 0 should ensure a dead tty

	/* At this point, the tty->count == 0 should ensure a dead tty