Hi Thomas, I love your patch! Yet something to improve: [auto build test ERROR on next-20200914] [also build test ERROR on v5.9-rc5] [cannot apply to linuxtv-media/master drm-intel/for-linux-next tegra/for-next linus/master v5.9-rc5 v5.9-rc4 v5.9-rc3] [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/Thomas-Zimmermann/dma-buf-Flag-v... base: f965d3ec86fa89285db0fbb983da76ba9c398efa config: x86_64-randconfig-a004-20200913 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b2c32c90bab09a6e2c1f370429db26017a182143) 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 # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): drivers/dma-buf/heaps/heap-helpers.c:269:10: error: incompatible function pointer types initializing 'int (*)(struct dma_buf *, struct dma_buf_map *)' with an expression of type 'void *(struct dma_buf *)' [-Werror,-Wincompatible-function-pointer-types] .vmap = dma_heap_dma_buf_vmap, ^~~~~~~~~~~~~~~~~~~~~ .vunmap = dma_heap_dma_buf_vunmap, ^~~~~~~~~~~~~~~~~~~~~~~ 2 errors generated. # https://github.com/0day-ci/linux/commit/7fd403952126005980734501c5d0de5e1... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Thomas-Zimmermann/dma-buf-Flag-vmap-ed-memory-as-system-or-I-O-memory/20200914-192712 git checkout 7fd403952126005980734501c5d0de5e13b3673b vim +270 drivers/dma-buf/heaps/heap-helpers.c 5248eb12fea890a John Stultz 2019-12-03 259 5248eb12fea890a John Stultz 2019-12-03 260 const struct dma_buf_ops heap_helper_ops = { 5248eb12fea890a John Stultz 2019-12-03 261 .map_dma_buf = dma_heap_map_dma_buf, 5248eb12fea890a John Stultz 2019-12-03 262 .unmap_dma_buf = dma_heap_unmap_dma_buf, 5248eb12fea890a John Stultz 2019-12-03 263 .mmap = dma_heap_mmap, 5248eb12fea890a John Stultz 2019-12-03 264 .release = dma_heap_dma_buf_release, 5248eb12fea890a John Stultz 2019-12-03 265 .attach = dma_heap_attach, 5248eb12fea890a John Stultz 2019-12-03 266 .detach = dma_heap_detach, 5248eb12fea890a John Stultz 2019-12-03 267 .begin_cpu_access = dma_heap_dma_buf_begin_cpu_access, 5248eb12fea890a John Stultz 2019-12-03 268 .end_cpu_access = dma_heap_dma_buf_end_cpu_access, 5248eb12fea890a John Stultz 2019-12-03 @269 .vmap = dma_heap_dma_buf_vmap, 5248eb12fea890a John Stultz 2019-12-03 @270 .vunmap = dma_heap_dma_buf_vunmap, --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org