diff options
| -rw-r--r-- | drivers/tty/n_tty.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index fa5cb4654c4..064616542cb 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -115,13 +115,14 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x, } /** - * n_tty_set__room - receive space + * n_tty_set_room - receive space * @tty: terminal * - * Called by the driver to find out how much data it is - * permitted to feed to the line discipline without any being lost - * and thus to manage flow control. Not serialized. Answers for the - * "instant". + * Sets tty->receive_room to reflect the currently available space + * in the input buffer, and re-schedules the flip buffer work if space + * just became available. + * + * Locks: Concurrent update is protected with read_lock */ static void n_tty_set_room(struct tty_struct *tty) @@ -129,8 +130,10 @@ static void n_tty_set_room(struct tty_struct *tty) struct n_tty_data *ldata = tty->disc_data; int left; int old_left; + unsigned long flags; + + raw_spin_lock_irqsave(&ldata->read_lock, flags); - /* ldata->read_cnt is not read locked ? */ if (I_PARMRK(tty)) { /* Multiply read_cnt by 3, since each byte might take up to * three times as many spaces when PARMRK is set (depending on @@ -150,6 +153,8 @@ static void n_tty_set_room(struct tty_struct *tty) old_left = tty->receive_room; tty->receive_room = left; + raw_spin_unlock_irqrestore(&ldata->read_lock, flags); + /* Did this open up the receive buffer? We may need to flip */ if (left && !old_left) { WARN_RATELIMIT(tty->port->itty == NULL, @@ -1872,7 +1877,6 @@ do_it_again: retval = -ERESTARTSYS; break; } - /* FIXME: does n_tty_set_room need locking ? */ n_tty_set_room(tty); timeout = schedule_timeout(timeout); continue; |