[linux-next:master 8508/11648] include/asm-generic/bitops/find.h:164:16: error: implicit declaration of function '__fls'; did you mean '__ffs'?

[kernel test robot <lkp@xxxxxxxxx>]

Hi Yury,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   e99d8a8495175df8cb8b739f8cf9b0fc9d0cd3b5
commit: bd083065154285baeb8af54147adac634a4e0b38 [8508/11648] lib: add fast path for find_first_*_bit() and find_last_bit()
config: h8300-randconfig-r013-20210411 (attached as .config)
compiler: h8300-linux-gcc (GCC) 9.3.0
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
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=bd083065154285baeb8af54147adac634a4e0b38
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout bd083065154285baeb8af54147adac634a4e0b38
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=h8300 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   In file included from arch/h8300/include/asm/bitops.h:167,
                    from include/linux/bitops.h:32,
                    from include/linux/log2.h:12,
                    from include/asm-generic/getorder.h:8,
                    from include/asm-generic/page.h:95,
                    from arch/h8300/include/asm/page.h:5,
                    from arch/h8300/include/asm/string.h:8,
                    from include/linux/string.h:21,
                    from include/linux/uuid.h:12,
                    from include/linux/mod_devicetable.h:13,
                    from scripts/mod/devicetable-offsets.c:3:
   include/asm-generic/bitops/find.h: In function 'find_last_bit':
>> include/asm-generic/bitops/find.h:164:16: error: implicit declaration of function '__fls'; did you mean '__ffs'? [-Werror=implicit-function-declaration]
     164 |   return val ? __fls(val) : size;
         |                ^~~~~
         |                __ffs
   In file included from arch/h8300/include/asm/bitops.h:177,
                    from include/linux/bitops.h:32,
                    from include/linux/log2.h:12,
                    from include/asm-generic/getorder.h:8,
                    from include/asm-generic/page.h:95,
                    from arch/h8300/include/asm/page.h:5,
                    from arch/h8300/include/asm/string.h:8,
                    from include/linux/string.h:21,
                    from include/linux/uuid.h:12,
                    from include/linux/mod_devicetable.h:13,
                    from scripts/mod/devicetable-offsets.c:3:
   include/asm-generic/bitops/__fls.h: At top level:
>> include/asm-generic/bitops/__fls.h:13:38: error: conflicting types for '__fls'
      13 | static __always_inline unsigned long __fls(unsigned long word)
         |                                      ^~~~~
   In file included from arch/h8300/include/asm/bitops.h:167,
                    from include/linux/bitops.h:32,
                    from include/linux/log2.h:12,
                    from include/asm-generic/getorder.h:8,
                    from include/asm-generic/page.h:95,
                    from arch/h8300/include/asm/page.h:5,
                    from arch/h8300/include/asm/string.h:8,
                    from include/linux/string.h:21,
                    from include/linux/uuid.h:12,
                    from include/linux/mod_devicetable.h:13,
                    from scripts/mod/devicetable-offsets.c:3:
   include/asm-generic/bitops/find.h:164:16: note: previous implicit declaration of '__fls' was here
     164 |   return val ? __fls(val) : size;
         |                ^~~~~
   cc1: some warnings being treated as errors
   make[2]: *** [scripts/Makefile.build:116: scripts/mod/devicetable-offsets.s] Error 1
   make[2]: Target '__build' not remade because of errors.
   make[1]: *** [Makefile:1234: prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:215: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +164 include/asm-generic/bitops/find.h

   149	
   150	#ifndef find_last_bit
   151	/**
   152	 * find_last_bit - find the last set bit in a memory region
   153	 * @addr: The address to start the search at
   154	 * @size: The number of bits to search
   155	 *
   156	 * Returns the bit number of the last set bit, or size.
   157	 */
   158	static inline
   159	unsigned long find_last_bit(const unsigned long *addr, unsigned long size)
   160	{
   161		if (small_const_nbits(size)) {
   162			unsigned long val = *addr & GENMASK(size - 1, 0);
   163	
 > 164			return val ? __fls(val) : size;
   165		}
   166	
   167		return _find_last_bit(addr, size);
   168	}
   169	#endif
   170	

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

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