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Date:   Fri, 4 Aug 2023 11:10:14 +0800
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Cc:     baolu.lu@linux.intel.com, "Liu, Yi L" <yi.l.liu@intel.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        "iommu@lists.linux.dev" <iommu@lists.linux.dev>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 05/12] iommu: Change the return value of
 dev_iommu_get()
Content-Language: en-US
To:     "Tian, Kevin" <kevin.tian@intel.com>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Nicolin Chen <nicolinc@nvidia.com>
References: <20230727054837.147050-1-baolu.lu@linux.intel.com>
 <20230727054837.147050-6-baolu.lu@linux.intel.com>
 <BN9PR11MB52769A468F912B7D395878ED8C08A@BN9PR11MB5276.namprd11.prod.outlook.com>
From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <BN9PR11MB52769A468F912B7D395878ED8C08A@BN9PR11MB5276.namprd11.prod.outlook.com>
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On 2023/8/3 15:59, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Thursday, July 27, 2023 1:49 PM
>>
>> Make dev_iommu_get() return 0 for success and error numbers for failure.
>> This will make the code neat and readable. No functionality changes.
>>
>> Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> ---
>>   drivers/iommu/iommu.c | 19 +++++++++++--------
>>   1 file changed, 11 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 00309f66153b..4ba3bb692993 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -290,20 +290,20 @@ void iommu_device_unregister(struct
>> iommu_device *iommu)
>>   }
>>   EXPORT_SYMBOL_GPL(iommu_device_unregister);
>>
>> -static struct dev_iommu *dev_iommu_get(struct device *dev)
>> +static int dev_iommu_get(struct device *dev)
>>   {
>>   	struct dev_iommu *param = dev->iommu;
>>
>>   	if (param)
>> -		return param;
>> +		return 0;
>>
>>   	param = kzalloc(sizeof(*param), GFP_KERNEL);
>>   	if (!param)
>> -		return NULL;
>> +		return -ENOMEM;
>>
>>   	mutex_init(&param->lock);
>>   	dev->iommu = param;
>> -	return param;
>> +	return 0;
>>   }
>>
> 
> Jason's series [1] has been queued. Time to refine according to
> the discussion in [2].
> 
> [1] https://lore.kernel.org/linux-iommu/ZLFYXlSBZrlxFpHM@8bytes.org/
> [2] https://lore.kernel.org/linux-iommu/c815fa2b-00df-91e1-8353-8258773957e4@linux.intel.com/

I'm not sure I understand your point here. This only changes the return
value of dev_iommu_get() to make the code more concise.

Best regards,
baolu