if (len < 0)
ep = (usb_pipein(pipe) ? usb_dev->ep_in : usb_dev->ep_out) [usb_pipeendpoint(pipe)]; if (!ep || len < 0)
int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe, 			void *data, int len, int *actual_length, int timeout){	struct urb *urb;	if (len < 0)		return -EINVAL;	urb=usb_alloc_urb(0, GFP_KERNEL);	if (!urb)		return -ENOMEM;	usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,			  usb_api_blocking_completion, NULL);	return usb_start_wait_urb(urb, timeout, actual_length);}