Hi David,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on kdave/for-next]
[also build test ERROR on ext4/dev fuse/for-next xfs-linux/for-next tip/perf/core linux/master linus/master v5.12-rc6 next-20210408]
[cannot apply to hnaz-linux-mm/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/David-Howells/mm-Split-page_has_private-in-two-to-better-handle-PG_private_2/20210409-051632
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
config: s390-debug_defconfig (attached as .config)
compiler: s390-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/a00a255f7bf637156368e8545b2c64e39c93718b
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review David-Howells/mm-Split-page_has_private-in-two-to-better-handle-PG_private_2/20210409-051632
        git checkout a00a255f7bf637156368e8545b2c64e39c93718b
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=s390 

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

All errors (new ones prefixed by >>):

   arch/s390/kernel/uv.c: In function 'expected_page_refs':
>> arch/s390/kernel/uv.c:178:7: error: implicit declaration of function 'page_has_private'; did you mean 'page_private'? [-Werror=implicit-function-declaration]
     178 |   if (page_has_private(page))
         |       ^~~~~~~~~~~~~~~~
         |       page_private
   cc1: some warnings being treated as errors


vim +178 arch/s390/kernel/uv.c

214d9bbcd3a672 Claudio Imbrenda 2020-01-21  162  
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  163  /*
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  164   * Calculate the expected ref_count for a page that would otherwise have no
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  165   * further pins. This was cribbed from similar functions in other places in
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  166   * the kernel, but with some slight modifications. We know that a secure
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  167   * page can not be a huge page for example.
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  168   */
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  169  static int expected_page_refs(struct page *page)
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  170  {
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  171  	int res;
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  172  
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  173  	res = page_mapcount(page);
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  174  	if (PageSwapCache(page)) {
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  175  		res++;
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  176  	} else if (page_mapping(page)) {
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  177  		res++;
214d9bbcd3a672 Claudio Imbrenda 2020-01-21 @178  		if (page_has_private(page))
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  179  			res++;
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  180  	}
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  181  	return res;
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  182  }
214d9bbcd3a672 Claudio Imbrenda 2020-01-21  183  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org