Re: [PATCH bpf-next v4 3/5] bpf: Inline calls to bpf_loop when callback is known

[kernel test robot <lkp@xxxxxxxxx>]

Hi Eduard,

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/Eduard-Zingerman/bpf_loop-inlining/20220609-033007
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: arm-randconfig-r014-20220608 (https://download.01.org/0day-ci/archive/20220609/202206092228.SWNGbTFO-lkp@xxxxxxxxx/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 971e13d69e3e7b687213fef22952be6a328c426c)
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
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/intel-lab-lkp/linux/commit/10671a6a0479bb7ee4d437c4ce7307f198cb96fd
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Eduard-Zingerman/bpf_loop-inlining/20220609-033007
        git checkout 10671a6a0479bb7ee4d437c4ce7307f198cb96fd
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash kernel/bpf/

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

All warnings (new ones prefixed by >>):

>> kernel/bpf/verifier.c:7111:6: warning: no previous prototype for function 'update_loop_inline_state' [-Wmissing-prototypes]
   void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
        ^
   kernel/bpf/verifier.c:7111:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
   ^
   static 
>> kernel/bpf/verifier.c:14318:18: warning: no previous prototype for function 'inline_bpf_loop' [-Wmissing-prototypes]
   struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
                    ^
   kernel/bpf/verifier.c:14318:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
   ^
   static 
   2 warnings generated.


vim +/update_loop_inline_state +7111 kernel/bpf/verifier.c

  7110	
> 7111	void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
  7112	{
  7113		struct bpf_loop_inline_state *state = &cur_aux(env)->loop_inline_state;
  7114		struct bpf_reg_state *regs = cur_regs(env);
  7115		struct bpf_reg_state *flags_reg = &regs[BPF_REG_4];
  7116	
  7117		int flags_is_zero =
  7118			register_is_const(flags_reg) && flags_reg->var_off.value == 0;
  7119	
  7120		if (state->initialized) {
  7121			state->fit_for_inline &=
  7122				flags_is_zero &&
  7123				state->callback_subprogno == subprogno;
  7124		} else {
  7125			state->initialized = 1;
  7126			state->fit_for_inline = flags_is_zero;
  7127			state->callback_subprogno = subprogno;
  7128		}
  7129	}
  7130	

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