Re: [PATCH v3 8/9] media: chips-media: wave6: Add Wave6 control driver

[Krzysztof Kozlowski <krzk@kernel.org>]

On 01/09/2025 10:13, Nas Chung wrote:
> Hi, Krzysztof.
> 
> Thanks for the feedback.
> 
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzk@kernel.org>
>> Sent: Friday, August 29, 2025 11:06 PM
>> To: Nas Chung <nas.chung@chipsnmedia.com>; mchehab@kernel.org;
>> hverkuil@xs4all.nl; robh@kernel.org; krzk+dt@kernel.org;
>> conor+dt@kernel.org; shawnguo@kernel.org; s.hauer@pengutronix.de
>> Cc: linux-media@vger.kernel.org; devicetree@vger.kernel.org; linux-
>> kernel@vger.kernel.org; linux-imx@nxp.com; linux-arm-
>> kernel@lists.infradead.org; jackson.lee <jackson.lee@chipsnmedia.com>;
>> lafley.kim <lafley.kim@chipsnmedia.com>; Ming Qian <ming.qian@oss.nxp.com>
>> Subject: Re: [PATCH v3 8/9] media: chips-media: wave6: Add Wave6 control
>> driver
>>
>> On 29/08/2025 10:46, Nas Chung wrote:
>>> +
>>> +static void wave6_vpu_load_firmware(const struct firmware *fw, void
>> *context)
>>> +{
>>> +	struct wave6_vpu_device *vpu = context;
>>> +
>>> +	guard(mutex)(&vpu->lock);
>>
>> Why? How could this be called in parallel, before the probe?
> 
> This callback is called asynchronously via firmware_request_nowait_nowarn().
> In practice, I observed a case where the callback was executing
> while the device's release() function was being called.

Indeed. Now I wonder how does it protect from concurrent remove()?

Best regards,
Krzysztof