Hi Eric,

I love your patch! Yet something to improve:

[auto build test ERROR on iommu/next]
[also build test ERROR on linus/master v5.6-rc6 next-20200320]
[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/Eric-Auger/SMMUv3-Nested-Stage-Setup-IOMMU-part/20200321-040627
base:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: arm-exynos_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.2.0
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=9.2.0 make.cross ARCH=arm 

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

All errors (new ones prefixed by >>):

   In file included from drivers/gpu/drm/exynos/exynos_drm_dma.c:7:
>> include/linux/dma-iommu.h:90:1: error: expected identifier or '(' before '{' token
      90 | {
         | ^
   In file included from drivers/gpu/drm/exynos/exynos_drm_dma.c:7:
   include/linux/dma-iommu.h:89:1: warning: 'iommu_dma_unbind_guest_msi' declared 'static' but never defined [-Wunused-function]
      89 | iommu_dma_unbind_guest_msi(struct iommu_domain *domain, dma_addr_t giova);
         | ^~~~~~~~~~~~~~~~~~~~~~~~~~

vim +90 include/linux/dma-iommu.h

    87	
    88	static inline void
    89	iommu_dma_unbind_guest_msi(struct iommu_domain *domain, dma_addr_t giova);
  > 90	{
    91	}
    92	

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0-DAY CI Kernel Test Service, Intel Corporation
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