linux-kernel - Re: [PATCH v5 2/5] media: imx-jpeg: Reset slot data pointers when free data

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Message-ID: <34b8d290-4b33-4d26-86c4-b7da08a735a0@oss.nxp.com>
Date: Mon, 21 Apr 2025 15:39:54 +0800
From: "Ming Qian(OSS)" <ming.qian@....nxp.com>
To: Nicolas Dufresne <nicolas@...fresne.ca>, mchehab@...nel.org,
 hverkuil-cisco@...all.nl, mirela.rabulea@....nxp.com
Cc: shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
 festevam@...il.com, xiahong.bao@....com, eagle.zhou@....com,
 linux-imx@....com, imx@...ts.linux.dev, linux-media@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v5 2/5] media: imx-jpeg: Reset slot data pointers when
 free data

Hi Nicolas,

On 2025/4/18 20:49, Nicolas Dufresne wrote:
> Le vendredi 18 avril 2025 à 15:08 +0800, ming.qian@....nxp.com a écrit :
>> From: Ming Qian <ming.qian@....nxp.com>
>>
>> To make the function mxc_jpeg_alloc_slot_data() and
>> mxc_jpeg_free_slot_data() safe to be called multiple times. Ensure that
>> the slot data pointers are reset to NULL and handles are set to 0 after
>> freeing the coherent memory.
> 
> Perhaps:
> 
>     media: imx-jpeg: Reset slot data pointers when freed
> 
> 
>     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.
> 

Thanks for help improve the commit message,
I'll apply it and make a v6 patch

Regards,
Ming

>>
>> Fixes: 2db16c6ed72c ("media: imx-jpeg: Add V4L2 driver for i.MX8 JPEG Encoder/Decoder")
>> Signed-off-by: Ming Qian <ming.qian@....nxp.com>
>> ---
>> v5
>> - Make a single patch to reset the slot data pointers when free data
>>
>>   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 2f7ee5dfa93d..b2f7e9ad1885 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;
>>   }
> 
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@...labora.com>