TTY: fix close of uninitialised ports

Make sure we do not make tty-driver callbacks or wait for port to drain
on uninitialised ports (e.g. when open failed) in
tty_port_close_start().

No callback, such as flush_buffer or wait_until_sent, needs to be made
on a port that has never been opened. Neither does it make much sense to
add drain delay for an uninitialised port.

Currently a drain delay of up to two seconds could be added when a tty
fails to open.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 8 deletions

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 20426ccbd58b..969c3e675a76 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -487,14 +487,16 @@ int tty_port_close_start(struct tty_port *port,
         set_bit(ASYNCB_CLOSING, &port->flags);
         tty->closing = 1;
         spin_unlock_irqrestore(&port->lock, flags);
-        /* Don't block on a stalled port, just pull the chain */
-        if (tty->flow_stopped)
-                tty_driver_flush_buffer(tty);
-        if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
-                        port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
-                tty_wait_until_sent_from_close(tty, port->closing_wait);
-        if (port->drain_delay)
-                tty_port_drain_delay(port, tty);
+
+        if (test_bit(ASYNCB_INITIALIZED, &port->flags)) {
+                /* Don't block on a stalled port, just pull the chain */
+                if (tty->flow_stopped)
+                        tty_driver_flush_buffer(tty);
+                if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
+                        tty_wait_until_sent_from_close(tty, port->closing_wait);
+                if (port->drain_delay)
+                        tty_port_drain_delay(port, tty);
+        }
         /* Flush the ldisc buffering */
         tty_ldisc_flush(tty);