Hi "Christian,

I love your patch! Yet something to improve:

[auto build test ERROR on hnaz-linux-mm/master]
[also build test ERROR on drm-intel/for-linux-next drm-tip/drm-tip linus/master v5.9-rc5 next-20200915]
[cannot apply to tegra-drm/drm/tegra/for-next drm-exynos/exynos-drm-next drm/drm-next]
[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/Christian-K-nig/drm-shmem-helpers-revert-Redirect-mmap-for-imported-dma-buf/20200914-222921
base:   https://github.com/hnaz/linux-mm master
config: sh-allmodconfig (attached as .config)
compiler: sh4-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
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sh 

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 >>):

   sh4-linux-ld: drivers/dma-buf/dma-buf.o: in function `dma_buf_mmap':
>> (.text+0x8dc): undefined reference to `vma_set_file'

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