Re: [PATCH v17 02/12] media: mediatek: jpeg: fix jpeg buffer payload size setting

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] media: mtk-jpeg: unnecessary duplication of vb2_set_plane_payload()
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commit c0c8c5e4f25d1e1a980b86dc79d9084a8c169924
Author: Kyrie Wu <kyrie.wu@mediatek.com>

media: mediatek: jpeg: fix jpeg buffer payload size setting

For multi-core jpegdec, if one core gets a resolution change event, the
payload size needs to change but cannot be changed immediately while others
decode, leading to mismatch warnings. This patch modifies the buffer prepare
function to clamp the payload size to the buffer length.

> diff --git a/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c b/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
> index 41c4cf8dc2626..34135706a4ac3 100644
> --- a/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c
> +++ b/drivers/media/platform/mediatek/jpeg/mtk_jpeg_core.c

[ ... ]

> @@ -710,12 +711,20 @@ static int mtk_jpeg_buf_prepare(struct vb2_buffer *vb)
>  
>  	for (i = 0; i < q_data->fmt->colplanes; i++) {
>  		plane_fmt = q_data->pix_mp.plane_fmt[i];
> +		max_size = plane_fmt.sizeimage;
> +
>  		if (ctx->enable_exif &&
> -		    q_data->fmt->fourcc == V4L2_PIX_FMT_JPEG)
> -			vb2_set_plane_payload(vb, i, plane_fmt.sizeimage +
> -					      MTK_JPEG_MAX_EXIF_SIZE);
> -		else
> -			vb2_set_plane_payload(vb, i,  plane_fmt.sizeimage);
> +			q_data->fmt->fourcc == V4L2_PIX_FMT_JPEG) {
> +			max_size += MTK_JPEG_MAX_EXIF_SIZE;
> +
> +			vb2_set_plane_payload(vb, i,
> +					      MIN(vb->planes[i].length,
> +						  max_size));
> +		} else {
> +			vb2_set_plane_payload(vb, i,
> +					      MIN(plane_fmt.sizeimage,
> +						  vb->planes[i].length));
> +		}

[Severity: Low]
This isn't a bug, but does mtk_jpeg_buf_prepare() unnecessarily duplicate the
vb2_set_plane_payload() call and clamping logic here?

Since max_size is already initialized to plane_fmt.sizeimage before the
conditional, could this be simplified by only adding MTK_JPEG_MAX_EXIF_SIZE
to max_size inside the if block, and then doing a single
vb2_set_plane_payload() call outside the branches?

>  	}
>  
>  	return 0;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260922091530.241762-1-kyrie.wu@mediatek.com?part=2