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Commit 3ff51a19 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
Browse files

tty: Remove TTY_HUPPING 



Now that tty_ldisc_hangup() does not drop the tty lock, it is no
longer possible to observe TTY_HUPPING while holding the tty lock
on another cpu.

Remove TTY_HUPPING bit definition.

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 c8483bc9

drivers/tty/tty_io.c

+1 −11
Original line number Diff line number Diff line
@@ -690,9 +690,6 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) 
		return;

	}



	/* some functions below drop BTM, so we need this bit */

	set_bit(TTY_HUPPING, &tty->flags);



	/* inuse_filps is protected by the single tty lock,

	   this really needs to change if we want to flush the

	   workqueue with the lock held */
@@ -717,10 +714,6 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) 
	while (refs--)

		tty_kref_put(tty);



	/*

	 * it drops BTM and thus races with reopen

	 * we protect the race by TTY_HUPPING

	 */

	tty_ldisc_hangup(tty);



	spin_lock_irq(&tty->ctrl_lock);
@@ -752,8 +745,6 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) 
	 * can't yet guarantee all that.

	 */

	set_bit(TTY_HUPPED, &tty->flags);

	clear_bit(TTY_HUPPING, &tty->flags);



	tty_unlock(tty);



	if (f)
@@ -1461,8 +1452,7 @@ static int tty_reopen(struct tty_struct *tty) 
{

	struct tty_driver *driver = tty->driver;



	if (test_bit(TTY_CLOSING, &tty->flags) ||

			test_bit(TTY_HUPPING, &tty->flags))

	if (test_bit(TTY_CLOSING, &tty->flags))

		return -EIO;



	if (driver->type == TTY_DRIVER_TYPE_PTY &&

drivers/tty/tty_ldisc.c

+1 −2
Original line number Diff line number Diff line
@@ -544,8 +544,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) 


	old_ldisc = tty->ldisc;



	if (test_bit(TTY_HUPPING, &tty->flags) ||

	    test_bit(TTY_HUPPED, &tty->flags)) {

	if (test_bit(TTY_HUPPED, &tty->flags)) {

		/* We were raced by the hangup method. It will have stomped

		   the ldisc data and closed the ldisc down */

		tty_ldisc_enable_pair(tty, o_tty);

include/linux/tty.h

+0 −1
Original line number Diff line number Diff line
@@ -321,7 +321,6 @@ struct tty_file_private { 
#define TTY_PTY_LOCK 		16	/* pty private */

#define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */

#define TTY_HUPPED 		18	/* Post driver->hangup() */

#define TTY_HUPPING 		21	/* ->hangup() in progress */

#define TTY_LDISC_HALTED	22	/* Line discipline is halted */



#define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))