diff options
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index c5b848a..fa0170e 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -558,29 +558,29 @@ static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout) * have been halted for this to guarantee it remains idle. * * Caller must hold legacy and ->ldisc_mutex. + * + * NB: tty_set_ldisc() is prevented from changing the ldisc concurrently + * with this function by checking the TTY_HUPPING flag. */ static bool tty_ldisc_hangup_wait_idle(struct tty_struct *tty) { - while (tty->ldisc) { /* Not yet closed */ - if (atomic_read(&tty->ldisc->users) != 1) { - char cur_n[TASK_COMM_LEN], tty_n[64]; - long timeout = 3 * HZ; - tty_unlock(tty); - - while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) { - timeout = MAX_SCHEDULE_TIMEOUT; - printk_ratelimited(KERN_WARNING - "%s: waiting (%s) for %s took too long, but we keep waiting...\n", - __func__, get_task_comm(cur_n, current), - tty_name(tty, tty_n)); - } - /* must reacquire both locks and preserve lock order */ - mutex_unlock(&tty->ldisc_mutex); - tty_lock(tty); - mutex_lock(&tty->ldisc_mutex); - continue; + char cur_n[TASK_COMM_LEN], tty_n[64]; + long timeout = 3 * HZ; + + if (tty->ldisc) { /* Not yet closed */ + tty_unlock(tty); + + while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) { + timeout = MAX_SCHEDULE_TIMEOUT; + printk_ratelimited(KERN_WARNING + "%s: waiting (%s) for %s took too long, but we keep waiting...\n", + __func__, get_task_comm(cur_n, current), + tty_name(tty, tty_n)); } - break; + /* must reacquire both locks and preserve lock order */ + mutex_unlock(&tty->ldisc_mutex); + tty_lock(tty); + mutex_lock(&tty->ldisc_mutex); } return !!tty->ldisc; } |