Re: [PATCH] firewire: fix warnings to generate UAPI documentation

[Randy Dunlap]

Hi,

On 6/1/23 07:49, Takashi Sakamoto wrote:
> Any target to generate UAPI documentation reports warnings to missing
> annotation for padding member in structures added recently.
> 
> This commit suppresses the warnings.
> 
> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Closes: https://lore.kernel.org/lkml/20230531135306.43613a59@xxxxxxxxxxxxxxxx/
> Fixes: 7c22d4a92bb2 ("firewire: cdev: add new event to notify request subaction with time stamp")
> Fixes: fc2b52cf2e0e ("firewire: cdev: add new event to notify response subaction with time stamp")
> Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
> ---
>  include/uapi/linux/firewire-cdev.h | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 

You can do it as this patch shows, or you can hide those padding fields as
described in Documentation/doc-guide/kernel-doc.rst:

Inside a struct or union description, you can use the ``private:`` and
``public:`` comment tags. Structure fields that are inside a ``private:``
area are not listed in the generated output documentation.

The ``private:`` and ``public:`` tags must begin immediately following a
``/*`` comment marker. They may optionally include comments between the
``:`` and the ending ``*/`` marker.

See below.

> diff --git a/include/uapi/linux/firewire-cdev.h b/include/uapi/linux/firewire-cdev.h
> index 99e823935427..1f2c9469f921 100644
> --- a/include/uapi/linux/firewire-cdev.h
> +++ b/include/uapi/linux/firewire-cdev.h
> @@ -130,6 +130,9 @@ struct fw_cdev_event_response {
>   * @length:	Data length, i.e. the response's payload size in bytes
>   * @request_tstamp:	The time stamp of isochronous cycle at which the request was sent.
>   * @response_tstamp:	The time stamp of isochronous cycle at which the response was sent.
> + * @padding:	Padding to keep the size of structure as multiples of 8 in various architectures
> + *		since 4 byte alignment is used for 8 byte of object type in System V ABI for i386
> + *		architecture.

You could drop that change.

>   * @data:	Payload data, if any
>   *
>   * This event is sent when the stack receives a response to an outgoing request
> @@ -155,10 +158,6 @@ struct fw_cdev_event_response2 {
>  	__u32 length;
>  	__u32 request_tstamp;
>  	__u32 response_tstamp;

	/* private: */
> -	/*
> -	 * Padding to keep the size of structure as multiples of 8 in various architectures since
> -	 * 4 byte alignment is used for 8 byte of object type in System V ABI for i386 architecture.
> -	 */
>  	__u32 padding;

	/* public: */

>  	__u32 data[];
>  };
> @@ -231,6 +230,9 @@ struct fw_cdev_event_request2 {
>   * @handle:	Reference to the kernel-side pending request
>   * @length:	Data length, i.e. the request's payload size in bytes
>   * @tstamp:	The time stamp of isochronous cycle at which the request arrived.
> + * @padding:	Padding to keep the size of structure as multiples of 8 in various architectures
> + *		since 4 byte alignment is used for 8 byte of object type in System V ABI for i386
> + *		architecture.

drop that.

>   * @data:	Incoming data, if any
>   *
>   * This event is sent when the stack receives an incoming request to an address
> @@ -284,10 +286,6 @@ struct fw_cdev_event_request3 {
>  	__u32 handle;
>  	__u32 length;
>  	__u32 tstamp;

	/* private: */

> -	/*
> -	 * Padding to keep the size of structure as multiples of 8 in various architectures since
> -	 * 4 byte alignment is used for 8 byte of object type in System V ABI for i386 architecture.
> -	 */
>  	__u32 padding;

	/* public: */

>  	__u32 data[];
>  };

-- 
~Randy