Subject: Re: [PATCH net-next v5 7/7] docs: netlink: document the sub-type attribute property

From: Bagas Sanjaya <[email-masked]>
Date: Mon, 27 Mar 2023 19:45:55 +0700

On Mon, Mar 27, 2023 at 09:31:38AM +0100, Donald Hunter wrote:
> diff --git a/Documentation/userspace-api/netlink/genetlink-legacy.rst b/Documentation/userspace-api/netlink/genetlink-legacy.rst
> index b8fdcf7f6615..802875a37a27 100644
> --- a/Documentation/userspace-api/netlink/genetlink-legacy.rst
> +++ b/Documentation/userspace-api/netlink/genetlink-legacy.rst
> @@ -234,6 +234,20 @@ specify a sub-type.
>            type: binary
>            struct: vport-stats
>  
> +C Arrays
> +--------
> +
> +Legacy families also use ``binary`` attributes to encapsulate C arrays. The
> +``sub-type`` is used to identify the type of scalar to extract.
> +
> +.. code-block:: yaml
> +
> +  attributes:
> +    -
> +      name: ports
> +      type: binary
> +      sub-type: u32
> +
>  Multi-message DO
>  ----------------
>  
> diff --git a/Documentation/userspace-api/netlink/specs.rst b/Documentation/userspace-api/netlink/specs.rst
> index a22442ba1d30..2e4acde890b7 100644
> --- a/Documentation/userspace-api/netlink/specs.rst
> +++ b/Documentation/userspace-api/netlink/specs.rst
> @@ -254,6 +254,16 @@ rather than depend on what is specified in the spec file.
>  The validation policy in the kernel is formed by combining the type
>  definition (``type`` and ``nested-attributes``) and the ``checks``.
>  
> +sub-type
> +~~~~~~~~
> +
> +Legacy families have special ways of expressing arrays. ``sub-type`` can be
> +used to define the type of array members in case array members are not
> +fully defined as attributes (in a bona fide attribute space). For instance
> +a C array of u32 values can be specified with ``type: binary`` and
> +``sub-type: u32``. Binary types and legacy array formats are described in
> +more detail in :doc:`genetlink-legacy`.
> +
>  operations
>  ----------
>  

The doc LGTM, thanks!

Reviewed-by: Bagas Sanjaya <[email-masked]>

-- 
An old man doll... just what I always wanted! - Clara