[PATCH v6 2/5] media: imx-jpeg: Reset slot data pointers when freed

[Frank Li]

On Mon, Apr 21, 2025 at 04:12:53PM +0800, ming.qian at oss.nxp.com wrote:
> From: Ming Qian <ming.qian at oss.nxp.com>
>
> Ensure that the slot data pointers are reset to NULL and handles are
> set to 0 after freeing the coherent memory. This makes he function
> mxc_jpeg_alloc_slot_data() and mxc_jpeg_free_slot_data() safe to be
> called multiple times.
>
> Fixes: 2db16c6ed72c ("media: imx-jpeg: Add V4L2 driver for i.MX8 JPEG Encoder/Decoder")
> Signed-off-by: Ming Qian <ming.qian at oss.nxp.com>
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>

Reviewed-by: Frank Li <Frank.Li at nxp.com>

> ---
> v6
> - Improve commit message
>
> v5
> - Split the resetting pointer when freed to a separate patch
> ---
>  drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> index ad2284e87985..29d3d4b08dd1 100644
> --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> @@ -758,16 +758,22 @@ static void mxc_jpeg_free_slot_data(struct mxc_jpeg_dev *jpeg)
>  	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
>  			  jpeg->slot_data.desc,
>  			  jpeg->slot_data.desc_handle);
> +	jpeg->slot_data.desc = NULL;
> +	jpeg->slot_data.desc_handle = 0;
>
>  	/* free descriptor for encoder configuration phase / decoder DHT */
>  	dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
>  			  jpeg->slot_data.cfg_desc,
>  			  jpeg->slot_data.cfg_desc_handle);
> +	jpeg->slot_data.cfg_desc_handle = 0;
> +	jpeg->slot_data.cfg_desc = NULL;
>
>  	/* free configuration stream */
>  	dma_free_coherent(jpeg->dev, MXC_JPEG_MAX_CFG_STREAM,
>  			  jpeg->slot_data.cfg_stream_vaddr,
>  			  jpeg->slot_data.cfg_stream_handle);
> +	jpeg->slot_data.cfg_stream_vaddr = NULL;
> +	jpeg->slot_data.cfg_stream_handle = 0;
>
>  	jpeg->slot_data.used = false;
>  }
> --
> 2.43.0-rc1
>