Re: [RFC PATCH bpf-next v2 4/6] bpf: Add common attr support for map_create

[Eduard Zingerman <eddyz87@gmail.com>]

On Fri, 2025-09-12 at 00:33 +0800, Leon Hwang wrote:

[...]

> @@ -1355,6 +1356,18 @@ static int map_create(union bpf_attr *attr, bool kernel)
>  	if (err)
>  		return -EINVAL;
>  
> +	if (common_attrs->log_buf) {
> +		log = kvzalloc(sizeof(*log), GFP_KERNEL);
> +		if (!log)
> +			return -ENOMEM;
> +		err = bpf_vlog_init(log, BPF_LOG_FIXED, u64_to_user_ptr(common_attrs->log_buf),
> +				    common_attrs->log_size, NULL);

Maybe use common_attrs->log_level instead of BPF_LOG_FIXED?
Just for consistent behavior with program and btf load operations.

> +		if (err) {
> +			kvfree(log);
> +			return err;
> +		}
> +	}
> +
>  	/* check BPF_F_TOKEN_FD flag, remember if it's set, and then clear it
>  	 * to avoid per-map type checks tripping on unknown flag
>  	 */

[...]

> @@ -1565,6 +1605,10 @@ static int map_create(union bpf_attr *attr, bool kernel)
>  	bpf_map_free(map);
>  put_token:
>  	bpf_token_put(token);
> +	if (err && log)
> +		(void) bpf_vlog_finalize(log, &log_true_size);
> +	if (log)
> +		kvfree(log);
>  	return err;
>  }

+1 to Andrii's suggestion to report log size back,
just for consistency reasons.