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, 4 insertions, 4 deletions

diff --git a/drivers/usb/serial/empeg.c b/drivers/usb/serial/empeg.c
index a6ab5b58d9ca..1072e847280f 100644
--- a/drivers/usb/serial/empeg.c
+++ b/drivers/usb/serial/empeg.c
@@ -33,9 +33,8 @@
  *      Moved MOD_DEC_USE_COUNT to end of empeg_close().
  *
  * (12/03/2000) gb
- *      Added port->port.tty->ldisc.set_termios(port->port.tty, NULL) to
- *      empeg_open(). This notifies the tty driver that the termios have
- *      changed.
+ *      Added tty->ldisc.set_termios(port, tty, NULL) to empeg_open().
+ *      This notifies the tty driver that the termios have changed.
  *
  * (11/13/2000) gb
  *      Moved tty->low_latency = 1 from empeg_read_bulk_callback() to
@@ -354,7 +353,7 @@ static void empeg_read_bulk_callback(struct urb *urb)
 
         usb_serial_debug_data(debug, &port->dev, __func__,
                                                 urb->actual_length, data);
-        tty = port->port.tty;
+        tty = tty_port_tty_get(&port->port);
 
         if (urb->actual_length) {
                 tty_buffer_request_room(tty, urb->actual_length);
@@ -362,6 +361,7 @@ static void empeg_read_bulk_callback(struct urb *urb)
                 tty_flip_buffer_push(tty);
                 bytes_in += urb->actual_length;
         }
+        tty_kref_put(tty);
 
         /* Continue trying to always read  */
         usb_fill_bulk_urb(