diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-11-05 13:11:41 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-06 14:57:27 -0800 |
| commit | 9191aaaa82d3149767125d58b2d260a3749d9f5e (patch) | |
| tree | c551a4b7588fb105c12c45fad1eec2dddff1541d | |
| parent | 3f40f5b2a22110754ce469f5722bade8aeb241e5 (diff) | |
tty: Allow safe access to termios for set_ldisc() handlers
Allow a tty driver to safely access termios settings while handling
the set_ldisc() notification. UART drivers use the set_ldisc()
notification to check if the N_PPS line discipline is being enabled;
if so, modem status interrupts may also need to be enabled. Conversely,
modem status interrupts may need to be disabled if switching away
from the N_PPS line discipline.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index b66a81d0549..3737f55272d 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -572,8 +572,11 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) tty_ldisc_restore(tty, old_ldisc); } - if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) + if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) { + down_read(&tty->termios_rwsem); tty->ops->set_ldisc(tty); + up_read(&tty->termios_rwsem); + } /* At this point we hold a reference to the new ldisc and a reference to the old ldisc, or we hold two references to |