Re: [PATCH v3 04/15] iommu: Move bus setup to IOMMU device registration

Baolu Lu
2022-07-06T02:35:48Z

On 2022/7/6 01:08, Robin Murphy wrote:
> @@ -202,12 +210,32 @@ int iommu_device_register(struct iommu_device *iommu,
> spin_lock(&iommu_device_lock);
> list_add_tail(&iommu->list, &iommu_device_list);
> spin_unlock(&iommu_device_lock);
> +
> + for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) {
> + struct bus_type *bus = iommu_buses[i];
> + int err;
> +
> + if (bus->iommu_ops && bus->iommu_ops != ops) {
> + err = -EBUSY;
> + } else {
> + bus->iommu_ops = ops;
> + err = bus_iommu_probe(bus);
> + }
> + if (err) {
> + iommu_device_unregister(iommu);
> + return err;
> + }
> + }
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(iommu_device_register);

With bus_set_iommu() retired, my understanding is that now we embrace
the first-come-first-serve policy for bus->iommu_ops setting. This will
lead to problem in different iommu_ops for different bus case. Did I
overlook anything?

Best regards,
baolu