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

[Mukesh Ojha]

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@xxxxxxxxxxxxxxx
>
> > Signed-off-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx>
> > ---
> >   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