Re: [PATCH v8 12/12] iommu: Use refcount for fault data access

[Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>]

On 12/11/23 11:24 PM, Jason Gunthorpe wrote:
> > @@ -282,22 +313,15 @@ EXPORT_SYMBOL_GPL(iommu_page_response);
> >    */
> >   int iopf_queue_flush_dev(struct device *dev)
> >   {
> > -	int ret = 0;
> > -	struct iommu_fault_param *iopf_param;
> > -	struct dev_iommu *param = dev->iommu;
> > +	struct iommu_fault_param *iopf_param = iopf_get_dev_fault_param(dev);
> >   
> > -	if (!param)
> > +	if (!iopf_param)
> >   		return -ENODEV;
> And this also seems unnecessary, it is a bug to call this after
> iopf_queue_remove_device() right? Just

Yes. They both are called from the iommu driver. The iommu driver should
guarantee this.

> rcu_derefernce(param->fault_param, true) and WARN_ON NULL.

Okay, sure.

Best regards,
baolu