tty: Move packet mode flow control notifications to pty driver

[firefly-linux-kernel-4.4.55.git] / drivers / tty / tty_io.c

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 8fbad3410c7581038b195510b7636fa85cd135d4..c249ff1d51ceab8de81f0160a202317fea836167 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -908,8 +908,7 @@ void no_tty(void)
  *     stop_tty        -       propagate flow control
  *     @tty: tty to stop
  *
- *     Perform flow control to the driver. For PTY/TTY pairs we
- *     must also propagate the TIOCKPKT status. May be called
+ *     Perform flow control to the driver. May be called
  *     on an already stopped device and will not re-call the driver
  *     method.
  *
@@ -919,64 +918,58 @@ void no_tty(void)
  *     but not always.
  *
  *     Locking:
- *             Uses the tty control lock internally
+ *             flow_lock
  */
 
-void stop_tty(struct tty_struct *tty)
+void __stop_tty(struct tty_struct *tty)
 {
-       unsigned long flags;
-       spin_lock_irqsave(&tty->ctrl_lock, flags);
-       if (tty->stopped) {
-               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+       if (tty->stopped)
                return;
-       }
        tty->stopped = 1;
-       if (tty->link && tty->link->packet) {
-               tty->ctrl_status &= ~TIOCPKT_START;
-               tty->ctrl_status |= TIOCPKT_STOP;
-               wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
-       }
-       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        if (tty->ops->stop)
                (tty->ops->stop)(tty);
 }
 
+void stop_tty(struct tty_struct *tty)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&tty->flow_lock, flags);
+       __stop_tty(tty);
+       spin_unlock_irqrestore(&tty->flow_lock, flags);
+}
 EXPORT_SYMBOL(stop_tty);
 
 /**
  *     start_tty       -       propagate flow control
  *     @tty: tty to start
  *
- *     Start a tty that has been stopped if at all possible. Perform
- *     any necessary wakeups and propagate the TIOCPKT status. If this
- *     is the tty was previous stopped and is being started then the
- *     driver start method is invoked and the line discipline woken.
+ *     Start a tty that has been stopped if at all possible. If this
+ *     tty was previous stopped and is now being started, the driver
+ *     start method is invoked and the line discipline woken.
  *
  *     Locking:
- *             ctrl_lock
+ *             flow_lock
  */
 
-void start_tty(struct tty_struct *tty)
+void __start_tty(struct tty_struct *tty)
 {
-       unsigned long flags;
-       spin_lock_irqsave(&tty->ctrl_lock, flags);
-       if (!tty->stopped || tty->flow_stopped) {
-               spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+       if (!tty->stopped || tty->flow_stopped)
                return;
-       }
        tty->stopped = 0;
-       if (tty->link && tty->link->packet) {
-               tty->ctrl_status &= ~TIOCPKT_STOP;
-               tty->ctrl_status |= TIOCPKT_START;
-               wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
-       }
-       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
        if (tty->ops->start)
                (tty->ops->start)(tty);
-       /* If we have a running line discipline it may need kicking */
        tty_wakeup(tty);
 }
 
+void start_tty(struct tty_struct *tty)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&tty->flow_lock, flags);
+       __start_tty(tty);
+       spin_unlock_irqrestore(&tty->flow_lock, flags);
+}
 EXPORT_SYMBOL(start_tty);
 
 /* We limit tty time update visibility to every 8 seconds or so. */
@@ -1544,13 +1537,14 @@ static void release_one_tty(struct work_struct *work)
        struct tty_struct *tty =
                container_of(work, struct tty_struct, hangup_work);
        struct tty_driver *driver = tty->driver;
+       struct module *owner = driver->owner;
 
        if (tty->ops->cleanup)
                tty->ops->cleanup(tty);
 
        tty->magic = 0;
        tty_driver_kref_put(driver);
-       module_put(driver->owner);
+       module_put(owner);
 
        spin_lock(&tty_files_lock);
        list_del_init(&tty->tty_files);
@@ -3018,6 +3012,7 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
        INIT_WORK(&tty->hangup_work, do_tty_hangup);
        mutex_init(&tty->atomic_write_lock);
        spin_lock_init(&tty->ctrl_lock);
+       spin_lock_init(&tty->flow_lock);
        INIT_LIST_HEAD(&tty->tty_files);
        INIT_WORK(&tty->SAK_work, do_SAK_work);