pipe_map
vm_map_remove(pipe_map,
buffer = (caddr_t) vm_map_min(pipe_map);
vm_map_lock(pipe_map);
vm_map_unlock(pipe_map);
error = vm_map_find_locked(pipe_map, NULL, 0, (vm_offset_t *)&buffer,
vm_map_unlock(pipe_map);
kmem_subinit(pipe_map, kernel_map, &minaddr, &maxaddr, maxpipekva,