Re: [PATCH][next] media: xilinx: Avoid -Wflex-array-member-not-at-end warning

Laurent Pinchart
2026-04-29T20:25:21Z

CC'ing Tomi Valkeinen.

On a side note, Tomi, can I send a patch to add you to the "XILINX VIDEO
IP CORES" section of MAINTAINERS ?

On Wed, Apr 29, 2026 at 01:55:27PM -0600, Gustavo A. R. Silva wrote:
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
>
> Use the TRAILING_OVERLAP() helper to fix the following warning:
>
> drivers/media/platform/xilinx/xilinx-dma.h:99:41: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>
> This helper creates a union between a flexible-array member (FAM)
> and a set of members that would otherwise follow it. This overlays
> the trailing members onto the FAM while preserving the original
> memory layout.
>
> Lastly, the static_assert() ensures the alignment between the FAM
> and struct data_chunk sgl; is not inadvertently changed, and it's
> intentionally placed inmediately after the related structure (that
> is, no blank line in between).
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> drivers/media/platform/xilinx/xilinx-dma.h | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/xilinx/xilinx-dma.h b/drivers/media/platform/xilinx/xilinx-dma.h
> index 18f77e1a7b39..65f6147ff6c6 100644
> --- a/drivers/media/platform/xilinx/xilinx-dma.h
> +++ b/drivers/media/platform/xilinx/xilinx-dma.h
> @@ -96,9 +96,14 @@ struct xvip_dma {
>
> struct dma_chan *dma;
> unsigned int align;
> - struct dma_interleaved_template xt;
> - struct data_chunk sgl;
> +
> + /* Must be last as it ends in a flexible-array member. */
> + TRAILING_OVERLAP(struct dma_interleaved_template, xt, sgl,
> + struct data_chunk sgl;
> + );
> };
> +static_assert(offsetof(struct xvip_dma, xt.sgl) ==
> + offsetof(struct xvip_dma, sgl));
>
> #define to_xvip_dma(vdev) container_of(vdev, struct xvip_dma, video)
>

--
Regards,

Laurent Pinchart