Re: [PATCH bpf-next 1/7] bpf: Create links for BPF struct_ops maps.

[kernel test robot <lkp@xxxxxxxxx>]

Hi Kui-Feng,

Thank you for the patch! Perhaps something to improve:

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

url:    https://github.com/intel-lab-lkp/linux/commits/Kui-Feng-Lee/bpf-Create-links-for-BPF-struct_ops-maps/20230215-061816
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20230214221718.503964-2-kuifeng%40meta.com
patch subject: [PATCH bpf-next 1/7] bpf: Create links for BPF struct_ops maps.
config: powerpc-allyesconfig (https://download.01.org/0day-ci/archive/20230215/202302150809.TbWg3iN6-lkp@xxxxxxxxx/config)
compiler: powerpc-linux-gcc (GCC) 12.1.0
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/c186fe88190559d4872279724d598b8d45ba3092
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Kui-Feng-Lee/bpf-Create-links-for-BPF-struct_ops-maps/20230215-061816
        git checkout c186fe88190559d4872279724d598b8d45ba3092
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash kernel/bpf/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Link: https://lore.kernel.org/oe-kbuild-all/202302150809.TbWg3iN6-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> kernel/bpf/bpf_struct_ops.c:736:5: warning: no previous prototype for 'link_create_struct_ops_map' [-Wmissing-prototypes]
     736 | int link_create_struct_ops_map(union bpf_attr *attr, bpfptr_t uattr)
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/link_create_struct_ops_map +736 kernel/bpf/bpf_struct_ops.c

   735	
 > 736	int link_create_struct_ops_map(union bpf_attr *attr, bpfptr_t uattr)
   737	{
   738		struct bpf_link_primer link_primer;
   739		struct bpf_map *map;
   740		struct bpf_link *link = NULL;
   741		int err;
   742	
   743		map = bpf_map_get(attr->link_create.prog_fd);
   744		if (map->map_type != BPF_MAP_TYPE_STRUCT_OPS)
   745			return -EINVAL;
   746	
   747		link = kzalloc(sizeof(*link), GFP_USER);
   748		if (!link) {
   749			err = -ENOMEM;
   750			goto err_out;
   751		}
   752		bpf_link_init(link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_map_lops, NULL);
   753		link->map = map;
   754	
   755		err = bpf_link_prime(link, &link_primer);
   756		if (err)
   757			goto err_out;
   758	
   759		return bpf_link_settle(&link_primer);
   760	
   761	err_out:
   762		bpf_map_put(map);
   763		kfree(link);
   764		return err;
   765	}
   766	

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https://github.com/intel/lkp-tests