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Date: Sun, 19 May 2024 18:14:12 +0800
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Cc: baolu.lu@linux.intel.com, "iommu@lists.linux.dev"
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Subject: Re: [PATCH v5 2/9] iommu: Replace sva_iommu with iommu_attach_handle
To: "Tian, Kevin" <kevin.tian@intel.com>, Jason Gunthorpe <jgg@ziepe.ca>,
 Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
 Robin Murphy <robin.murphy@arm.com>,
 Jean-Philippe Brucker <jean-philippe@linaro.org>,
 Nicolin Chen <nicolinc@nvidia.com>, "Liu, Yi L" <yi.l.liu@intel.com>,
 Jacob Pan <jacob.jun.pan@linux.intel.com>,
 Joel Granados <j.granados@samsung.com>
References: <20240430145710.68112-1-baolu.lu@linux.intel.com>
 <20240430145710.68112-3-baolu.lu@linux.intel.com>
 <BN9PR11MB527615219EEF0EF3EACCF38D8CEC2@BN9PR11MB5276.namprd11.prod.outlook.com>
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From: Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <BN9PR11MB527615219EEF0EF3EACCF38D8CEC2@BN9PR11MB5276.namprd11.prod.outlook.com>
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On 5/15/24 3:21 PM, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Tuesday, April 30, 2024 10:57 PM
>>
>>   #else
>> -static inline struct iommu_sva *
>> +static inline struct iommu_attach_handle *
>>   iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
>>   {
>> -	return NULL;
>> +	return ERR_PTR(-ENODEV);
>>   }
>>
> 
> this should be a separate fix.

Yes. It could be a fix.

> 
> existing drivers (idxd and uacce) only check IS_ERR() on the return
> value. A Null pointer may lead to an error reported at a later point.

Though I don't think it could cause any real problem because this
interface should always be called after the sva enabling one.

Best regards,
baolu