Re: [PATCH bpf-next v11 01/13] bpf: refactory struct_ops type initialization to a function.

Kui-Feng Lee
2023-11-21T23:53:10Z

On 11/9/23 17:11, Martin KaFai Lau wrote:
> On 11/6/23 12:12 PM, thinker.li@gmail.com wrote:
>> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
>> index db6176fb64dc..627cf1ea840a 100644
>> --- a/kernel/bpf/bpf_struct_ops.c
>> +++ b/kernel/bpf/bpf_struct_ops.c
>> @@ -110,102 +110,111 @@ const struct bpf_prog_ops
>> bpf_struct_ops_prog_ops = {
>>   static const struct btf_type *module_type;
>> -void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
>> +static void bpf_struct_ops_init_one(struct bpf_struct_ops *st_ops,
>> +                    struct btf *btf,
>> +                    struct bpf_verifier_log *log)
>>   {
>> -    s32 type_id, value_id, module_id;
>>       const struct btf_member *member;
>> -    struct bpf_struct_ops *st_ops;
>>       const struct btf_type *t;
>> +    s32 type_id, value_id;
>>       char value_name[128];
>>       const char *mname;
>> -    u32 i, j;
>> +    int i;
>> -    /* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
>> -#define BPF_STRUCT_OPS_TYPE(_name) BTF_TYPE_EMIT(struct
>> bpf_struct_ops_##_name);
>> -#include "bpf_struct_ops_types.h"
>> -#undef BPF_STRUCT_OPS_TYPE
>> +    if (strlen(st_ops->name) + VALUE_PREFIX_LEN >=
>> +        sizeof(value_name)) {
>> +        pr_warn("struct_ops name %s is too long\n",
>> +            st_ops->name);
>> +        return;
>> +    }
>> +    sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
>> -    module_id = btf_find_by_name_kind(btf, "module", BTF_KIND_STRUCT);
>> -    if (module_id < 0) {
>> -        pr_warn("Cannot find struct module in btf_vmlinux\n");
>> +    value_id = btf_find_by_name_kind(btf, value_name,
>> +                     BTF_KIND_STRUCT);
>> +    if (value_id < 0) {
>> +        pr_warn("Cannot find struct %s in btf_vmlinux\n",
>> +            value_name);
>
> "btf_vmlinux" needs to change in the pr_warn(). It should be btf->name
> but that may need a helper function to return btf->name.

Right! I will add a helper function to return the name.

>
>>           return;
>>       }
>> -    module_type = btf_type_by_id(btf, module_id);
>> -    for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
>> -        st_ops = bpf_struct_ops[i];
>> +    type_id = btf_find_by_name_kind(btf, st_ops->name,
>> +                    BTF_KIND_STRUCT);
>> +    if (type_id < 0) {
>> +        pr_warn("Cannot find struct %s in btf_vmlinux\n",
>
> Same here.