Hi Matthew,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc1 next-20190724]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox/Make-working-with-compound-pages-easier/20190722-030555
config: powerpc64-allyesconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=powerpc64 

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

Note: the linux-review/Matthew-Wilcox/Make-working-with-compound-pages-easier/20190722-030555 HEAD e1bb8b04ba8cf861b2610b0ae646ee49cb069568 builds fine.
      It only hurts bisectibility.

All error/warnings (new ones prefixed by >>):

   drivers/vfio/vfio_iommu_spapr_tce.c: In function 'tce_page_is_contained':
>> drivers/vfio/vfio_iommu_spapr_tce.c:193:9: error: called object 'page_shift' is not a function or function pointer
     return page_shift(compound_head(page)) >= page_shift;
            ^~~~~~~~~~
   drivers/vfio/vfio_iommu_spapr_tce.c:179:16: note: declared here
      unsigned int page_shift)
                   ^~~~~~~~~~
>> drivers/vfio/vfio_iommu_spapr_tce.c:194:1: warning: control reaches end of non-void function [-Wreturn-type]
    }
    ^

vim +/page_shift +193 drivers/vfio/vfio_iommu_spapr_tce.c

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