Subject: Re: [PATCH net-next] tools: ynl-gen: generate docs for <name>_max/_mask enums

From: Jakub Kicinski <[email-masked]>
Date: Tue, 13 Jun 2023 17:59:28 -0700

On Wed, 14 Jun 2023 01:17:09 +0200 Arkadiusz Kubalewski wrote:
> Including ynl generated uapi header files into source kerneldocs
> (rst files in Documentation/) produces warnings during documentation
> builds (i.e. make htmldocs)
> 
> Prevent warnings by generating also description for enums where rander_max
> was selected.

Do you reckon that documenting the meta-values makes sense, or should
we throw a:

/* private: */

comment in front of them so that kdoc ignores them? Does user space
have any use for those? If we want to document them...

> diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
> index 639524b59930..d78f7ae95092 100644
> --- a/include/uapi/linux/netdev.h
> +++ b/include/uapi/linux/netdev.h
> @@ -24,6 +24,7 @@
>   *   XDP buffer support in the driver napi callback.
>   * @NETDEV_XDP_ACT_NDO_XMIT_SG: This feature informs if netdev implements
>   *   non-linear XDP buffer support in ndo_xdp_xmit callback.
> + * @NETDEV_XDP_ACT_MASK: valid values mask

... I think we need to include some sort of indication that the value
will change as the uAPI is extended. Unlike the other values which are
set in stone, so to speak. "mask of currently defines values" ? Dunno.

>   */
>  enum netdev_xdp_act {
>  	NETDEV_XDP_ACT_BASIC = 1,
> diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
> index 639524b59930..d78f7ae95092 100644
> --- a/tools/include/uapi/linux/netdev.h
> +++ b/tools/include/uapi/linux/netdev.h
> @@ -24,6 +24,7 @@
>   *   XDP buffer support in the driver napi callback.
>   * @NETDEV_XDP_ACT_NDO_XMIT_SG: This feature informs if netdev implements
>   *   non-linear XDP buffer support in ndo_xdp_xmit callback.
> + * @NETDEV_XDP_ACT_MASK: valid values mask
>   */
>  enum netdev_xdp_act {
>  	NETDEV_XDP_ACT_BASIC = 1,
> diff --git a/tools/net/ynl/ynl-gen-c.py b/tools/net/ynl/ynl-gen-c.py
> index 0b5e0802a9a7..0d396bf98c27 100755
> --- a/tools/net/ynl/ynl-gen-c.py
> +++ b/tools/net/ynl/ynl-gen-c.py
> @@ -2011,6 +2011,7 @@ def render_uapi(family, cw):
>          # Write kdoc for enum and flags (one day maybe also structs)
>          if const['type'] == 'enum' or const['type'] == 'flags':
>              enum = family.consts[const['name']]
> +            name_pfx = const.get('name-prefix', f"{family.name}-{const['name']}-")
>  
>              if enum.has_doc():
>                  cw.p('/**')
> @@ -2022,10 +2023,18 @@ def render_uapi(family, cw):
>                      if entry.has_doc():
>                          doc = '@' + entry.c_name + ': ' + entry['doc']
>                          cw.write_doc_line(doc)
> +                if const.get('render-max', False):
> +                    if const['type'] == 'flags':
> +                        doc = '@' + c_upper(name_pfx + 'mask') + ': valid values mask'
> +                        cw.write_doc_line(doc)
> +                    else:
> +                        doc = '@' + c_upper(name_pfx + 'max') + ': max valid value'
> +                        cw.write_doc_line(doc)
> +                        doc = '@__' + c_upper(name_pfx + 'max') + ': do not use'

This one is definitely a candidate for /* private: */

> +                        cw.write_doc_line(doc)
>                  cw.p(' */')
>  
>              uapi_enum_start(family, cw, const, 'name')
> -            name_pfx = const.get('name-prefix', f"{family.name}-{const['name']}-")
>              for entry in enum.entries.values():
>                  suffix = ','
>                  if entry.value_change:

-- 
pw-bot: cr