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

[Laurent Pinchart]

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 at kernel.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart at 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