Hi "Christian,

I love your patch! Perhaps something to improve:

[auto build test WARNING on drm-tip/drm-tip]
[also build test WARNING on next-20200922]
[cannot apply to drm-exynos/exynos-drm-next drm-intel/for-linux-next tegra-drm/drm/tegra/for-next linus/master drm/drm-next v5.9-rc6]
[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-ttm-add-ttm_bo_pin-ttm_bo_unpin/20200921-234857
base:   git://anongit.freedesktop.org/drm/drm-tip drm-tip
config: x86_64-randconfig-a005-20200921 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 4e8c028158b56d9c2142a62464e8e0686bde3584)
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@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/vmwgfx/vmwgfx_bo.c:518:8: warning: expression which evaluates to zero treated as a null pointer constant of type 'struct ttm_operation_ctx *' [-Wnon-literal-null-conversion]
                                      false, acc_size, NULL, NULL, NULL);
                                      ^~~~~
   1 warning generated.

# https://github.com/0day-ci/linux/commit/4f52191faabdaf44db9409b13ccea5ec0da52704
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Christian-K-nig/drm-ttm-add-ttm_bo_pin-ttm_bo_unpin/20200921-234857
git checkout 4f52191faabdaf44db9409b13ccea5ec0da52704
vim +518 drivers/gpu/drm/vmwgfx/vmwgfx_bo.c

   489	
   490	/**
   491	 * vmw_bo_create_kernel - Create a pinned BO for internal kernel use.
   492	 *
   493	 * @dev_priv: Pointer to the device private struct
   494	 * @size: size of the BO we need
   495	 * @placement: where to put it
   496	 * @p_bo: resulting BO
   497	 *
   498	 * Creates and pin a simple BO for in kernel use.
   499	 */
   500	int vmw_bo_create_kernel(struct vmw_private *dev_priv, unsigned long size,
   501				 struct ttm_placement *placement,
   502				 struct ttm_buffer_object **p_bo)
   503	{
   504		unsigned npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
   505		struct ttm_buffer_object *bo;
   506		size_t acc_size;
   507		int ret;
   508	
   509		bo = kzalloc(sizeof(*bo), GFP_KERNEL);
   510		if (unlikely(!bo))
   511			return -ENOMEM;
   512	
   513		acc_size = ttm_round_pot(sizeof(*bo));
   514		acc_size += ttm_round_pot(npages * sizeof(void *));
   515		acc_size += ttm_round_pot(sizeof(struct ttm_tt));
   516		ret = ttm_bo_init_reserved(&dev_priv->bdev, bo, size,
   517					   ttm_bo_type_device, placement, 0,
 > 518					   false, acc_size, NULL, NULL, NULL);
   519		if (unlikely(ret))
   520			goto error_free;
   521	
   522		ttm_bo_pin(bo);
   523		ttm_bo_unreserve(bo);
   524		*p_bo = bo;
   525	
   526		return 0;
   527	
   528	error_free:
   529		kfree(bo);
   530		return ret;
   531	}
   532	

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