Re: [PATCH v12 7/9] firmware: qcom: scm: Fix __scm->dev assignement

[Mukesh Ojha <quic_mojha@quicinc.com>]

On 3/3/2024 12:55 AM, Bjorn Andersson wrote:
> On Tue, Feb 27, 2024 at 09:23:06PM +0530, Mukesh Ojha wrote:
>> qcom_scm_is_available() gives wrong indication if __scm
>> is initialized but __scm->dev is not.
>>
>> Fix this appropriately by making sure if __scm is
>> initialized and then it is associated with its
>> device.
>>
> 
> This seems like a bug fix, and should as such have a Fixes: tag and
> probably Cc: stable@vger.kernel.org
> 
>> Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
>> ---
>>   drivers/firmware/qcom/qcom_scm.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
>> index 6c252cddd44e..6f14254c0c10 100644
>> --- a/drivers/firmware/qcom/qcom_scm.c
>> +++ b/drivers/firmware/qcom/qcom_scm.c
>> @@ -1859,6 +1859,7 @@ static int qcom_scm_probe(struct platform_device *pdev)
>>   	if (!scm)
>>   		return -ENOMEM;
>>   
>> +	scm->dev = &pdev->dev;
>>   	ret = qcom_scm_find_dload_address(&pdev->dev, &scm->dload_mode_addr);
>>   	if (ret < 0)
>>   		return ret;
>> @@ -1895,7 +1896,6 @@ static int qcom_scm_probe(struct platform_device *pdev)
>>   		return ret;
>>   
>>   	__scm = scm;
>> -	__scm->dev = &pdev->dev;
> 
> Is it sufficient to just move the line up, or do we need a barrier of
> some sort here?

Would be good to use, smp_mb() before the assignment
      __scm = scm
along with moving below line
__scm->dev = &pdev->dev

somewhere up.

-Mukesh

> 
> Regards,
> Bjorn
> 
>>   
>>   	init_completion(&__scm->waitq_comp);
>>   
>> -- 
>> 2.43.0.254.ga26002b62827
>>