Re: [PATCH v6 14/22] dma-buf: Introduce new locking convention

[kernel test robot <yujie.liu@intel.com>]

Hi Dmitry,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on next-20220527]
[cannot apply to drm/drm-next media-tree/master drm-intel/for-linux-next v5.18]
[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/intel-lab-lkp/linux/commits/Dmitry-Osipenko/Add-generic-memory-shrinker-to-VirtIO-GPU-and-Panfrost-DRM-drivers/20220527-075717
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git cdeffe87f790dfd1baa193020411ce9a538446d7
config: arm-randconfig-c002-20220524 (https://download.01.org/0day-ci/archive/20220528/202205280550.MWGs9cj4-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 134d7f9a4b97e9035150d970bd9e376043c4577e)
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 arm cross compiling tool for clang build
         # apt-get install binutils-arm-linux-gnueabi
         # https://github.com/intel-lab-lkp/linux/commit/97f090c47ec995a8cf3bced98526ee3eaa25f10f
         git remote add linux-review https://github.com/intel-lab-lkp/linux
         git fetch --no-tags linux-review Dmitry-Osipenko/Add-generic-memory-shrinker-to-VirtIO-GPU-and-Panfrost-DRM-drivers/20220527-075717
         git checkout 97f090c47ec995a8cf3bced98526ee3eaa25f10f
         # save the config file
         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm clang-analyzer

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <yujie.liu@intel.com>


clang-analyzer warnings: (new ones prefixed by >>)

 >> drivers/dma-buf/dma-buf.c:1339:3: warning: Undefined or garbage value returned to caller [clang-analyzer-core.uninitialized.UndefReturn]
                    return ret;
                    ^

vim +1339 drivers/dma-buf/dma-buf.c

4c78513e457f72 drivers/base/dma-buf.c    Daniel Vetter   2012-04-24  1327
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1328  static int dma_buf_vmap_locked(struct dma_buf *dmabuf, struct iosys_map *map)
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1329  {
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1330  	struct iosys_map ptr;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27 @1331  	int ret;
4c78513e457f72 drivers/base/dma-buf.c    Daniel Vetter   2012-04-24  1332
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1333  	dma_resv_assert_held(dmabuf->resv);
4c78513e457f72 drivers/base/dma-buf.c    Daniel Vetter   2012-04-24  1334
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1335  	if (dmabuf->vmapping_counter) {
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1336  		dmabuf->vmapping_counter++;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1337  		BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1338  		*map = dmabuf->vmap_ptr;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27 @1339  		return ret;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1340  	}
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1341
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1342  	BUG_ON(iosys_map_is_set(&dmabuf->vmap_ptr));
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1343
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1344  	ret = dmabuf->ops->vmap(dmabuf, &ptr);
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1345  	if (WARN_ON_ONCE(ret))
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1346  		return ret;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1347
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1348  	dmabuf->vmap_ptr = ptr;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1349  	dmabuf->vmapping_counter = 1;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1350
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1351  	*map = dmabuf->vmap_ptr;
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1352
97f090c47ec995 drivers/dma-buf/dma-buf.c Dmitry Osipenko 2022-05-27  1353  	return 0;
4c78513e457f72 drivers/base/dma-buf.c    Daniel Vetter   2012-04-24  1354  }
98f86c9e4ae320 drivers/base/dma-buf.c    Dave Airlie     2012-05-20  1355

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