USB: stop io performed by mos7720 upon close()

This fixes a problem where the mos7720 driver will make io to a device from
which it has been logically disconnected. It does so by introducing a flag by
which the generic usb serial code can signal the subdrivers their
disconnection and appropriate locking.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index ef1e430f7bfa..63b29b5332e6 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -129,6 +129,7 @@ struct usb_serial {
         struct usb_device *             dev;
         struct usb_serial_driver *      type;
         struct usb_interface *          interface;
+        unsigned char                   disconnected;
         unsigned char                   minor;
         unsigned char                   num_ports;
         unsigned char                   num_port_pointers;
@@ -138,6 +139,7 @@ struct usb_serial {
         char                            num_bulk_out;
         struct usb_serial_port *        port[MAX_NUM_PORTS];
         struct kref                     kref;
+        struct mutex                    disc_mutex;
         void *                          private;
 };
 #define to_usb_serial(d) container_of(d, struct usb_serial, kref)