[PATCH] synchronous control/bulk messaging

This one-liner fixes a problem in synchronous messaging
with usb_bulk_msg(), usb_control_msg(), and everything
that calls usb_control_msg():  you're not allowed to call
blocking functions when you're already on a wait queue.

A better fix would be to just stick the thread on the
wait queue _after_ submitting the URB, but that should
involve more testing than I have time for just now.

drivers/usb/core/message.c

@@ -36,7 +36,7 @@ static int usb_start_wait_urb(struct urb *urb, int timeout, int* actual_length)
 	add_wait_queue(&awd.wqh, &wait);
 
 	urb->context = &awd;
-	status = usb_submit_urb(urb, GFP_KERNEL);
+	status = usb_submit_urb(urb, GFP_ATOMIC);
 	if (status) {
 		// something went wrong
 		usb_free_urb(urb);