On Tue, Oct 8, 2024 at 2:02 AM Hou Tao <houtao@xxxxxxxxxxxxxxx> wrote:
>
> +#define MAX_DYNPTR_CNT_IN_MAP_KEY 4
> +
> static int map_check_btf(struct bpf_map *map, struct bpf_token *token,
> const struct btf *btf, u32 btf_key_id, u32 btf_value_id)
> {
> @@ -1103,6 +1113,40 @@ static int map_check_btf(struct bpf_map *map, struct bpf_token *token,
> if (!value_type || value_size != map->value_size)
> return -EINVAL;
>
> + if (btf_type_is_dynptr(btf, key_type))
> + map->key_record = btf_new_bpf_dynptr_record();
> + else
> + map->key_record = btf_parse_fields(btf, key_type, BPF_DYNPTR, map->key_size);
> + if (!IS_ERR_OR_NULL(map->key_record)) {
> + if (map->key_record->cnt > MAX_DYNPTR_CNT_IN_MAP_KEY) {
> + ret = -E2BIG;
> + goto free_map_tab;
Took me a while to grasp that map->key_record is only for dynptr fields
and map->record is for the rest except dynptr fields.
Maybe rename key_record to dynptr_fields ?
Or at least add a comment to struct bpf_map to explain
what each btf_record is for.
It's kinda arbitrary decision to support multiple dynptr-s per key
while other fields are not.
Maybe worth looking at generalizing it a bit so single btf_record
can have multiple of certain field kinds?
In addition to btf_record->cnt you'd need btf_record->dynptr_cnt
but that would be easier to extend in the future ?
