Hi Benjamin, kernel test robot noticed the following build warnings: [auto build test WARNING on 70ec81c2e2b4005465ad0d042e90b36087c36104] url: https://github.com/intel-lab-lkp/linux/commits/Benjamin-Tissoires/HID-rename-struct-hid_bpf_ops-into-hid_ops/20240528-212222 base: 70ec81c2e2b4005465ad0d042e90b36087c36104 patch link: https://lore.kernel.org/r/20240528-hid_bpf_struct_ops-v1-3-8c6663df27d8%40kernel.org patch subject: [PATCH HID 03/13] HID: bpf: implement HID-BPF through bpf_struct_ops config: i386-buildonly-randconfig-002-20240531 (https://download.01.org/0day-ci/archive/20240531/202405312035.U1rZN04z-lkp@xxxxxxxxx/config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240531/202405312035.U1rZN04z-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202405312035.U1rZN04z-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): In file included from include/linux/bpf_verifier.h:7:0, from drivers/hid/bpf/hid_bpf_struct_ops.c:10: drivers/hid/bpf/hid_bpf_struct_ops.c: In function 'hid_bpf_struct_ops_init': >> include/linux/bpf.h:1844:50: warning: statement with no effect [-Wunused-value] #define register_bpf_struct_ops(st_ops, type) ({ (void *)(st_ops); 0; }) ^~~~~~~~~~~~~~~~ drivers/hid/bpf/hid_bpf_struct_ops.c:244:9: note: in expansion of macro 'register_bpf_struct_ops' return register_bpf_struct_ops(&bpf_hid_bpf_ops, hid_bpf_ops); ^~~~~~~~~~~~~~~~~~~~~~~ vim +1844 include/linux/bpf.h c196906d50e360d Hou Tao 2021-10-25 1834 c196906d50e360d Hou Tao 2021-10-25 1835 int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, c196906d50e360d Hou Tao 2021-10-25 1836 union bpf_attr __user *uattr); c196906d50e360d Hou Tao 2021-10-25 1837 #endif f6be98d19985411 Kui-Feng Lee 2024-01-19 1838 int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, f6be98d19985411 Kui-Feng Lee 2024-01-19 1839 struct btf *btf, f6be98d19985411 Kui-Feng Lee 2024-01-19 1840 struct bpf_verifier_log *log); 1338b93346587a2 Kui-Feng Lee 2024-01-19 1841 void bpf_map_struct_ops_info_fill(struct bpf_map_info *info, struct bpf_map *map); 1611603537a4b88 Kui-Feng Lee 2024-02-08 1842 void bpf_struct_ops_desc_release(struct bpf_struct_ops_desc *st_ops_desc); 27ae7997a66174c Martin KaFai Lau 2020-01-08 1843 #else f6be98d19985411 Kui-Feng Lee 2024-01-19 @1844 #define register_bpf_struct_ops(st_ops, type) ({ (void *)(st_ops); 0; }) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1845 static inline bool bpf_try_module_get(const void *data, struct module *owner) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1846 { 85d33df357b6346 Martin KaFai Lau 2020-01-08 1847 return try_module_get(owner); 85d33df357b6346 Martin KaFai Lau 2020-01-08 1848 } 85d33df357b6346 Martin KaFai Lau 2020-01-08 1849 static inline void bpf_module_put(const void *data, struct module *owner) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1850 { 85d33df357b6346 Martin KaFai Lau 2020-01-08 1851 module_put(owner); 85d33df357b6346 Martin KaFai Lau 2020-01-08 1852 } 85d33df357b6346 Martin KaFai Lau 2020-01-08 1853 static inline int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, 85d33df357b6346 Martin KaFai Lau 2020-01-08 1854 void *key, 85d33df357b6346 Martin KaFai Lau 2020-01-08 1855 void *value) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1856 { 85d33df357b6346 Martin KaFai Lau 2020-01-08 1857 return -EINVAL; 85d33df357b6346 Martin KaFai Lau 2020-01-08 1858 } 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1859 static inline int bpf_struct_ops_link_create(union bpf_attr *attr) 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1860 { 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1861 return -EOPNOTSUPP; 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1862 } 1338b93346587a2 Kui-Feng Lee 2024-01-19 1863 static inline void bpf_map_struct_ops_info_fill(struct bpf_map_info *info, struct bpf_map *map) 1338b93346587a2 Kui-Feng Lee 2024-01-19 1864 { 1338b93346587a2 Kui-Feng Lee 2024-01-19 1865 } 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1866 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki