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

Randy Dunlap
2023-06-01T20:24:04Z

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@canb.auug.org.au>
> Closes: https://lore.kernel.org/lkml/20230531135306.43613a59@canb.auug.org.au/
> 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@sakamocchi.jp>
> ---
> 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