tree:   git://git.infradead.org/users/hch/block.git blkdev.h-includes
head:   48f7fda047613ceec07881f14a5eaf1ee19d4433
commit: cb48a9689b4fe34897d12d2e037b9f5094785832 [4/16] block: support delayed holder registration
config: sparc-defconfig (attached as .config)
compiler: sparc-linux-gcc (GCC) 10.3.0
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
        git remote add hch-block git://git.infradead.org/users/hch/block.git
        git fetch --no-tags hch-block blkdev.h-includes
        git checkout cb48a9689b4fe34897d12d2e037b9f5094785832
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=sparc 

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 >>):

   In file included from include/linux/blkdev.h:8,
                    from include/linux/blk-cgroup.h:23,
                    from include/linux/writeback.h:14,
                    from include/linux/memcontrol.h:22,
                    from include/linux/tracehook.h:50,
                    from arch/sparc/kernel/signal_32.c:22:
>> include/linux/genhd.h:335:12: error: 'bd_register_pending_holders' defined but not used [-Werror=unused-function]
     335 | static int bd_register_pending_holders(struct gendisk *disk)
         |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors


vim +/bd_register_pending_holders +335 include/linux/genhd.h

   320	
   321	#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
   322	int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
   323	void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
   324	int bd_register_pending_holders(struct gendisk *disk);
   325	#else
   326	static inline int bd_link_disk_holder(struct block_device *bdev,
   327					      struct gendisk *disk)
   328	{
   329		return 0;
   330	}
   331	static inline void bd_unlink_disk_holder(struct block_device *bdev,
   332						 struct gendisk *disk)
   333	{
   334	}
 > 335	static int bd_register_pending_holders(struct gendisk *disk)
   336	{
   337		return 0;
   338	}
   339	#endif /* CONFIG_BLOCK_HOLDER_DEPRECATED */
   340	

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