}
/**
- * 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)
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
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,
retval = -ERESTARTSYS;
break;
}
- /* FIXME: does n_tty_set_room need locking ? */
n_tty_set_room(tty);
timeout = schedule_timeout(timeout);
continue;