From 63d8cb3f19dabb409a09b4f2b8827934ab9365a3 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 8 Nov 2015 09:29:38 -0500 Subject: [PATCH] tty: Simplify tty_set_ldisc() exit handling Perform common exit for both successful and error exit handling in tty_set_ldisc(). Fixes unlikely possibility of failing to restart input kworker when switching to the same line discipline (noop case). Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_ldisc.c | 42 +++++++++++++---------------------------- 1 file changed, 13 insertions(+), 29 deletions(-) diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 7d43ff12f6e2..9ec125046343 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -529,34 +529,21 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) tty_lock(tty); retval = tty_ldisc_lock(tty, 5 * HZ); - if (retval) { - tty_ldisc_put(new_ldisc); - tty_unlock(tty); - return retval; - } + if (retval) + goto err; - /* - * Check the no-op case - */ + /* Check the no-op case */ + if (tty->ldisc->ops->num == ldisc) + goto out; - if (tty->ldisc->ops->num == ldisc) { - tty_ldisc_unlock(tty); - tty_ldisc_put(new_ldisc); - tty_unlock(tty); - return 0; + if (test_bit(TTY_HUPPED, &tty->flags)) { + /* We were raced by hangup */ + retval = -EIO; + goto out; } old_ldisc = tty->ldisc; - 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_unlock(tty); - tty_ldisc_put(new_ldisc); - tty_unlock(tty); - return -EIO; - } - /* Shutdown the old discipline. */ tty_ldisc_close(tty, old_ldisc); @@ -582,18 +569,15 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) the old ldisc (if it was restored as part of error cleanup above). In either case, releasing a single reference from the old ldisc is correct. */ - - tty_ldisc_put(old_ldisc); - - /* - * Allow ldisc referencing to occur again - */ + new_ldisc = old_ldisc; +out: tty_ldisc_unlock(tty); /* Restart the work queue in case no characters kick it off. Safe if already running */ tty_buffer_restart_work(tty->port); - +err: + tty_ldisc_put(new_ldisc); /* drop the extra reference */ tty_unlock(tty); return retval; } -- 2.39.2