Hi Desmond,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on next-20210813]
[also build test WARNING on v5.14-rc5]
[cannot apply to linus/master v5.14-rc5 v5.14-rc4 v5.14-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/Desmond-Cheong-Zhi-Xi/drm-avoid-races-with-modesetting-rights/20210815-234145
base:    4b358aabb93a2c654cd1dcab1a25a589f6e2b153
config: arc-randconfig-r031-20210815 (attached as .config)
compiler: arceb-elf-gcc (GCC) 11.2.0
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
        # https://github.com/0day-ci/linux/commit/cf6d8354b7d7953cd866fad004cbb189adfa074f
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Desmond-Cheong-Zhi-Xi/drm-avoid-races-with-modesetting-rights/20210815-234145
        git checkout cf6d8354b7d7953cd866fad004cbb189adfa074f
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arc 

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/drm_auth.c:483:6: warning: no previous prototype for 'master_flush' [-Wmissing-prototypes]
     483 | void master_flush(struct callback_head *cb)
         |      ^~~~~~~~~~~~


vim +/master_flush +483 drivers/gpu/drm/drm_auth.c

   479	
   480	/* After flushing, all readers that might have seen old master/lease
   481	 * permissions are guaranteed to have completed.
   482	 */
 > 483	void master_flush(struct callback_head *cb)
   484	{
   485		struct drm_device *dev = container_of(cb, struct drm_device,
   486						      master_flush_work);
   487	
   488		down_write(&dev->master_rwsem);
   489		up_write(&dev->master_rwsem);
   490	}
   491	

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