Hi Dan,

I love your patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[cannot apply to v5.4-rc6 next-20191108]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Dan-Williams/Memory-Hierarchy-Enable-target-node-lookups-for-reserved-memory/20191109-080607
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: x86_64-randconfig-d002-201944 (attached as .config)
compiler: gcc-7 (Debian 7.4.0-14) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   ld: drivers/nvdimm/e820.o: in function `e820_register_one':
>> drivers/nvdimm/e820.c:27: undefined reference to `numa_map_to_online_node'

vim +27 drivers/nvdimm/e820.c

    18	
    19	static int e820_register_one(struct resource *res, void *data)
    20	{
    21		struct nd_region_desc ndr_desc;
    22		struct nvdimm_bus *nvdimm_bus = data;
    23		int nid = memory_add_physaddr_to_target_node(res->start);
    24	
    25		memset(&ndr_desc, 0, sizeof(ndr_desc));
    26		ndr_desc.res = res;
  > 27		ndr_desc.numa_node = numa_map_to_online_node(nid);
    28		ndr_desc.target_node = nid;
    29		set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
    30		if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
    31			return -ENXIO;
    32		return 0;
    33	}
    34	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation