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Message-ID: <83c02530-230a-4ae0-8853-5da95c0ee814@linux.intel.com>
Date: Thu, 11 Apr 2024 21:13:17 +0800
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Cc: baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
 Will Deacon <will@kernel.org>, Robin Murphy <robin.murphy@arm.com>,
 Kevin Tian <kevin.tian@intel.com>, Tina Zhang <tina.zhang@intel.com>,
 Yi Liu <yi.l.liu@intel.com>, iommu@lists.linux.dev,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 12/12] iommu/vt-d: Retire struct intel_svm
To: Jason Gunthorpe <jgg@ziepe.ca>
References: <20240410020844.253535-1-baolu.lu@linux.intel.com>
 <20240410020844.253535-13-baolu.lu@linux.intel.com>
 <20240410154951.GH223006@ziepe.ca>
 <b24f3380-1ac3-41c4-9163-56c1dcff6297@linux.intel.com>
 <20240411130759.GJ223006@ziepe.ca>
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From: Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <20240411130759.GJ223006@ziepe.ca>
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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