Rewrite of bpf_analyzer from http://lxr.free-electrons.com/source/kernel/bpf/verifier.c#L3198 without gotos

verifier.c

/* Original: */

int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops,
                 void *priv)
{
    struct bpf_verifier_env *env;
    int ret;

    env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
    if (!env)
        return -ENOMEM;

    env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) *
                                 prog->len);
    ret = -ENOMEM;
    if (!env->insn_aux_data)
        goto err_free_env;
    env->prog = prog;
    env->analyzer_ops = ops;
    env->analyzer_priv = priv;

    /* grab the mutex to protect few globals used by verifier */
    mutex_lock(&bpf_verifier_lock);

    log_level = 0;

    env->explored_states = kcalloc(env->prog->len,
                                   sizeof(struct bpf_verifier_state_list *),
                                   GFP_KERNEL);
    ret = -ENOMEM;
    if (!env->explored_states)
        goto skip_full_check;

    ret = check_cfg(env);
    if (ret < 0)
        goto skip_full_check;

    env->allow_ptr_leaks = capable(CAP_SYS_ADMIN);

    ret = do_check(env);

skip_full_check:
    while (pop_stack(env, NULL) >= 0);
    free_states(env);

    mutex_unlock(&bpf_verifier_lock);
    vfree(env->insn_aux_data);
err_free_env:
    kfree(env);
    return ret;
}

/* Rewrite without gotos: */

int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, void *priv)
{
    struct bpf_verifier_env *env;
    int ret;

    env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
    ret = -ENOMEM;

    if (env)
    {
        env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) * prog->len);

        if (env->insn_aux_data)
        {
            env->prog = prog;
            env->analyzer_ops = ops;
            env->analyzer_priv = priv;

            /* grab the mutex to protect few globals used by verifier */
            mutex_lock(&bpf_verifier_lock);

            log_level = 0;

            env->explored_states = kcalloc(env->prog->len, sizeof(struct bpf_verifier_state_list *), GFP_KERNEL);

            if (env->explored_states)
            {
                ret = check_cfg(env);

                if (ret >= 0)
                {
                    env->allow_ptr_leaks = capable(CAP_SYS_ADMIN);
                    
                    ret = do_check(env);
                }
            }
            
            while (pop_stack(env, NULL) >= 0);
            {
                free_states(env);
            }
            
            mutex_unlock(&bpf_verifier_lock);
            
            vfree(env->insn_aux_data);
        }
        
        kfree(env);
    }
    
    return ret;
}