[PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.

This removes a lot of racy and buggy code by trying to check the status of the urb.

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

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/usb/serial/usb-serial.h b/drivers/usb/serial/usb-serial.h
index d1f0c4057fa6..57f92f054c75 100644
--- a/drivers/usb/serial/usb-serial.h
+++ b/drivers/usb/serial/usb-serial.h
@@ -69,6 +69,7 @@
  * usb_serial_port: structure for the specific ports of a device.
  * @serial: pointer back to the struct usb_serial owner of this port.
  * @tty: pointer to the corresponding tty for this port.
+ * @lock: spinlock to grab when updating portions of this structure.
  * @number: the number of the port (the minor number).
  * @interrupt_in_buffer: pointer to the interrupt in buffer for this port.
  * @interrupt_in_urb: pointer to the interrupt in struct urb for this port.
@@ -98,6 +99,7 @@
 struct usb_serial_port {
         struct usb_serial *     serial;
         struct tty_struct *     tty;
+        spinlock_t              lock;
         unsigned char           number;
 
         unsigned char *         interrupt_in_buffer;
@@ -117,6 +119,7 @@ struct usb_serial_port {
         unsigned char *         bulk_out_buffer;
         int                     bulk_out_size;
         struct urb *            write_urb;
+        int                     write_urb_busy;
         __u8                    bulk_out_endpointAddress;
 
         wait_queue_head_t       write_wait;