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tty: Remove TTY_HUPPING

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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: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2014-11-05 12:12:46 -05:00 committed by Greg Kroah-Hartman
parent c8483bc9de
commit 3ff51a199f
3 changed files with 2 additions and 14 deletions
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12
drivers/tty/tty_io.c
View file

@ -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 &&

3
drivers/tty/tty_ldisc.c
View file

@ -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);

1
include/linux/tty.h
View file

@ -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))