Re: [PATCH bpf-next] libbpf: Include linux/log2.h to use is_pow_of_2()

[kernel test robot <lkp@intel.com>]

Hi Tiezhu,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Tiezhu-Yang/libbpf-Include-linux-log2-h-to-use-is_pow_of_2/20220620-160053
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: s390-defconfig (https://download.01.org/0day-ci/archive/20220620/202206201942.DQpI2tgb-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 11.3.0
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://github.com/intel-lab-lkp/linux/commit/785c0dfdcebd7deec5cfaaf7bce252c40f30a350
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Tiezhu-Yang/libbpf-Include-linux-log2-h-to-use-is_pow_of_2/20220620-160053
        git checkout 785c0dfdcebd7deec5cfaaf7bce252c40f30a350
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=s390 prepare

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

All errors (new ones prefixed by >>):

   scripts/genksyms/parse.y: warning: 9 shift/reduce conflicts [-Wconflicts-sr]
   scripts/genksyms/parse.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr]
   scripts/genksyms/parse.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
   linker.c: In function 'linker_sanity_check_elf':
>> linker.c:722:49: error: implicit declaration of function 'is_pow_of_2'; did you mean 'is_power_of_2'? [-Werror=implicit-function-declaration]
     722 |                 if (sec->shdr->sh_addralign && !is_pow_of_2(sec->shdr->sh_addralign))
         |                                                 ^~~~~~~~~~~
         |                                                 is_power_of_2
>> linker.c:722:49: error: nested extern declaration of 'is_pow_of_2' [-Werror=nested-externs]
   libbpf.c: In function 'adjust_ringbuf_sz':
>> libbpf.c:5134:36: error: implicit declaration of function 'is_pow_of_2'; did you mean 'is_power_of_2'? [-Werror=implicit-function-declaration]
    5134 |         if ((sz % page_sz) == 0 && is_pow_of_2(sz / page_sz))
         |                                    ^~~~~~~~~~~
         |                                    is_power_of_2
>> libbpf.c:5134:36: error: nested extern declaration of 'is_pow_of_2' [-Werror=nested-externs]
   cc1: all warnings being treated as errors
   make[5]: *** [tools/build/Makefile.build:96: tools/bpf/resolve_btfids/libbpf/staticobjs/linker.o] Error 1
   make[5]: *** Waiting for unfinished jobs....
   cc1: all warnings being treated as errors
   make[5]: *** [tools/build/Makefile.build:96: tools/bpf/resolve_btfids/libbpf/staticobjs/libbpf.o] Error 1
   make[4]: *** [Makefile:157: tools/bpf/resolve_btfids/libbpf/staticobjs/libbpf-in.o] Error 2
   make[3]: *** [Makefile:55: tools/bpf/resolve_btfids//libbpf/libbpf.a] Error 2
   make[2]: *** [Makefile:76: bpf/resolve_btfids] Error 2
   make[1]: *** [Makefile:1344: tools/bpf/resolve_btfids] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:219: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.

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