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

Gustavo A. R. Silva
2026-04-29T22:47:30Z

On 4/29/26 14:28, Laurent Pinchart wrote:
> I forgot to ask, how do you want to get this merged? Will you collect
> all similar patches and send a tree-wide pull request, or should they be
> merged by individual subsystems ? In the latter case, Tomi, could you
> please handle this with other Xilinx patches ?

You folks can take this in your tree. :)

Thanks!
-Gustavo

>
> On Wed, Apr 29, 2026 at 11:24:50PM +0300, Laurent Pinchart wrote:
>> 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)
>>>
>