Re: [PATCH v2 12/12] iommu/vt-d: Retire struct intel_svm

[Baolu Lu <baolu.lu@linux.intel.com>]

On 2024/4/11 21:07, Jason Gunthorpe wrote:
>> +static void intel_mm_free_notifier(struct mmu_notifier *mn)
>> +{
>> +       kfree(container_of(mn, struct dmar_domain, notifier));
>> +}
>> +
>>   static const struct mmu_notifier_ops intel_mmuops = {
>>          .release = intel_mm_release,
>>          .arch_invalidate_secondary_tlbs =
>> intel_arch_invalidate_secondary_tlbs,
>> +       .free_notifier = intel_mm_free_notifier,
>>   };
>>
>>   static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
>> @@ -598,10 +604,8 @@ static void intel_svm_domain_free(struct iommu_domain
>> *domain)
>>   {
>>          struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>>
>> -       if (dmar_domain->notifier.ops)
>> -               mmu_notifier_unregister(&dmar_domain->notifier, domain->mm);
>> -
>> -       kfree(dmar_domain);
>> +       /* dmar_domain free is defered to the mmu free_notifier callback. */
>> +       mmu_notifier_put(&dmar_domain->notifier);
>>   }
> Yeah, that is better.
> 
> Also you need to have mmu notifier call on module unload when using
> this scheme.

The Intel IOMMU driver doesn't support being a module. It's always
built-in.

Best regards,
baolu