pickup_urb_and_free_priv
struct urb *pickup_urb_and_free_priv(struct vhci_device *vdev, __u32 seqnum);
urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);