Re: [PATCH net-next v4 7/7] docs: netlink: document the sub-type attribute property

From: Jakub Kicinski <kuba@kernel.org>
To: Donald Hunter <donald.hunter@gmail.com>
Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
	linux-doc@vger.kernel.org, donald.hunter@redhat.com
Subject: Re: [PATCH net-next v4 7/7] docs: netlink: document the sub-type attribute property
Date: Fri, 24 Mar 2023 20:57:22 -0700	[thread overview]
Message-ID: <20230324205722.7b6a9e70@kernel.org> (raw)
In-Reply-To: <20230324191900.21828-8-donald.hunter@gmail.com>

On Fri, 24 Mar 2023 19:19:00 +0000 Donald Hunter wrote:
> +sub-type
> +~~~~~~~~
> +
> +Attributes can have a ``sub-type`` that is interpreted in a ``type``
> +specific way. For example, an attribute with ``type: binary`` can have
> +``sub-type: u32`` which says to interpret the binary blob as an array of
> +``u32``. Binary types are described in more detail in
> +:doc:`genetlink-legacy`.

I think sub-type is only used for arrays? How about:

 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`.