relay_reserve
relay_reserve(log->relay.channel, log->vma->obj->base.size -
return relay_reserve(log->relay.channel, 0);
dest = relay_reserve(dev->relay_fwlog, hdrlen + len + 4);
dest = relay_reserve(dev->relay_fwlog, hdrlen + len + 4);
t = relay_reserve(bt->rchan, trace_len);
t = relay_reserve(bt->rchan, trace_len);