diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2013-03-11 21:44:24 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-19 00:32:46 +0100 |
| commit | 168942c9fa01916173a7b72ac67e1d218d571013 (patch) | |
| tree | a431ccb0dbe13b1cb4553effd607c00ac59c1be6 /drivers | |
| parent | n_tty: Don't flush buffer when closing ldisc (diff) | |
| download | linux-168942c9fa01916173a7b72ac67e1d218d571013.tar.xz linux-168942c9fa01916173a7b72ac67e1d218d571013.zip | |
tty: Refactor wait for ldisc refs out of tty_ldisc_hangup()
Refactor tty_ldisc_hangup() to extract standalone function,
tty_ldisc_hangup_wait_idle(), to wait for ldisc references
to be released.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 54 |
1 files changed, 36 insertions, 18 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index c641321b9404..c5b848a78e49 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -551,6 +551,41 @@ static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout) } /** + * tty_ldisc_hangup_wait_idle - wait for the ldisc to become idle + * @tty: tty to wait for + * + * Wait for the line discipline to become idle. The discipline must + * have been halted for this to guarantee it remains idle. + * + * Caller must hold legacy and ->ldisc_mutex. + */ +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; + } + break; + } + return !!tty->ldisc; +} + +/** * tty_set_ldisc - set line discipline * @tty: the terminal to set * @ldisc: the line discipline @@ -826,7 +861,6 @@ void tty_ldisc_hangup(struct tty_struct *tty) cancel_work_sync(&tty->port->buf.work); set_bit(TTY_LDISC_HALTED, &tty->flags); mutex_unlock(&tty->ldisc_mutex); -retry: tty_lock(tty); mutex_lock(&tty->ldisc_mutex); @@ -834,23 +868,7 @@ retry: 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 (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)); - } - mutex_unlock(&tty->ldisc_mutex); - goto retry; - } - + if (tty_ldisc_hangup_wait_idle(tty)) { if (reset == 0) { if (!tty_ldisc_reinit(tty, tty->termios.c_line)) |