diff options
| -rw-r--r-- | drivers/char/tty_ldisc.c | 50 |
1 files changed, 30 insertions, 20 deletions
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index 3f653f7d849..500e740ec5e 100644 --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -706,12 +706,13 @@ static void tty_reset_termios(struct tty_struct *tty) /** * tty_ldisc_reinit - reinitialise the tty ldisc * @tty: tty to reinit + * @ldisc: line discipline to reinitialize * - * Switch the tty back to N_TTY line discipline and leave the - * ldisc state closed + * Switch the tty to a line discipline and leave the ldisc + * state closed */ -static void tty_ldisc_reinit(struct tty_struct *tty) +static void tty_ldisc_reinit(struct tty_struct *tty, int ldisc) { struct tty_ldisc *ld; @@ -721,10 +722,10 @@ static void tty_ldisc_reinit(struct tty_struct *tty) /* * Switch the line discipline back */ - ld = tty_ldisc_get(N_TTY); + ld = tty_ldisc_get(ldisc); BUG_ON(IS_ERR(ld)); tty_ldisc_assign(tty, ld); - tty_set_termios_ldisc(tty, N_TTY); + tty_set_termios_ldisc(tty, ldisc); } /** @@ -745,6 +746,8 @@ static void tty_ldisc_reinit(struct tty_struct *tty) void tty_ldisc_hangup(struct tty_struct *tty) { struct tty_ldisc *ld; + int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS; + int err = 0; /* * FIXME! What are the locking issues here? This may me overdoing @@ -772,25 +775,32 @@ void tty_ldisc_hangup(struct tty_struct *tty) wake_up_interruptible_poll(&tty->read_wait, POLLIN); /* * Shutdown the current line discipline, and reset it to - * N_TTY. + * N_TTY if need be. + * + * Avoid racing set_ldisc or tty_ldisc_release */ - if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { - /* Avoid racing set_ldisc or tty_ldisc_release */ - mutex_lock(&tty->ldisc_mutex); - tty_ldisc_halt(tty); - if (tty->ldisc) { /* Not yet closed */ - /* Switch back to N_TTY */ - tty_ldisc_reinit(tty); - /* At this point we have a closed ldisc and we want to - reopen it. We could defer this to the next open but - it means auditing a lot of other paths so this is - a FIXME */ + mutex_lock(&tty->ldisc_mutex); + tty_ldisc_halt(tty); + /* At this point we have a closed ldisc and we want to + reopen it. We could defer this to the next open but + it means auditing a lot of other paths so this is + a FIXME */ + if (tty->ldisc) { /* Not yet closed */ + if (reset == 0) { + tty_ldisc_reinit(tty, tty->termios->c_line); + err = tty_ldisc_open(tty, tty->ldisc); + } + /* If the re-open fails or we reset then go to N_TTY. The + N_TTY open cannot fail */ + if (reset || err) { + tty_ldisc_reinit(tty, N_TTY); WARN_ON(tty_ldisc_open(tty, tty->ldisc)); - tty_ldisc_enable(tty); } - mutex_unlock(&tty->ldisc_mutex); - tty_reset_termios(tty); + tty_ldisc_enable(tty); } + mutex_unlock(&tty->ldisc_mutex); + if (reset) + tty_reset_termios(tty); } /** |