tty: usb-serial krefs

Use kref in the USB serial drivers so that we don't free tty structures
from under the URB receive handlers as has historically been the case if
you were unlucky. This also gives us a framework for general tty drivers to
use tty_port objects and refcount.

Contains two err->dev_err changes merged together to fix clashes in the
-next tree.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/usb/serial/kl5kusb105.c b/drivers/usb/serial/kl5kusb105.c
index b84dddc71124..ff3a07f5102f 100644
--- a/drivers/usb/serial/kl5kusb105.c
+++ b/drivers/usb/serial/kl5kusb105.c
@@ -658,7 +658,7 @@ static void klsi_105_read_bulk_callback(struct urb *urb)
         } else {
                 int bytes_sent = ((__u8 *) data)[0] +
                                  ((unsigned int) ((__u8 *) data)[1] << 8);
-                tty = port->port.tty;
+                tty = tty_port_tty_get(&port->port);
                 /* we should immediately resubmit the URB, before attempting
                  * to pass the data on to the tty layer. But that needs locking
                  * against re-entry an then mixed-up data because of
@@ -679,6 +679,7 @@ static void klsi_105_read_bulk_callback(struct urb *urb)
                 tty_buffer_request_room(tty, bytes_sent);
                 tty_insert_flip_string(tty, data + 2, bytes_sent);
                 tty_flip_buffer_push(tty);
+                tty_kref_put(tty);
 
                 /* again lockless, but debug info only */
                 priv->bytes_in += bytes_sent;