Re: [PATCH 7/8] iommu: Clean up open-coded ownership checks

[Robin Murphy]

On 19/01/2023 7:31 pm, Jason Gunthorpe wrote:
> On Thu, Jan 19, 2023 at 07:18:25PM +0000, Robin Murphy wrote:
> > diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> > index 270c3d9128ba..b2d3d309be1e 100644
> > --- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> > +++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
> > @@ -79,16 +79,6 @@ static struct qcom_iommu_domain *to_qcom_iommu_domain(struct iommu_domain *dom)
> >   
> >   static const struct iommu_ops qcom_iommu_ops;
> >   
> > -static struct qcom_iommu_dev * to_iommu(struct device *dev)
> > -{
> > -	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > -
> > -	if (!fwspec || fwspec->ops != &qcom_iommu_ops)
> > -		return NULL;
> > -
> > -	return dev_iommu_priv_get(dev);
> > -}
> > -
> >   static struct qcom_iommu_ctx * to_ctx(struct qcom_iommu_domain *d, unsigned asid)
> >   {
> >   	struct qcom_iommu_dev *qcom_iommu = d->iommu;
> > @@ -361,7 +351,7 @@ static void qcom_iommu_domain_free(struct iommu_domain *domain)
> >   
> >   static int qcom_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
> >   {
> > -	struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
> > +	struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
> >   	struct qcom_iommu_domain *qcom_domain = to_qcom_iommu_domain(domain);
> >   	int ret;
>
> The confusing checks for null qcom_iommu following this should go away
> too, right?
>
> It should not be possible to have an ops set on the device but have an
> invalid priv..

Yeah, this was just an audit of already-redundant fwspec->ops checks, 
but another one for redundant dev_iommu_priv checks is probably 
worthwhile too.

Cheers,
Robin.