From 3ff51a199f9e85aed843471bc10dae9e94dbb0fc Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Wed, 5 Nov 2014 12:12:46 -0500 Subject: [PATCH] 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: Alan Cox Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 12 +----------- drivers/tty/tty_ldisc.c | 3 +-- include/linux/tty.h | 1 - 3 files changed, 2 insertions(+), 14 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 9d1e247ee330..873793c426df 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -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 && diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 28858ebe2912..49001fa2ea2f 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -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); diff --git a/include/linux/tty.h b/include/linux/tty.h index b36b0b445c1f..ff0dd7aeaf3b 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -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)) -- 2.20.1