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Message-ID: <2501c884-7c78-d367-3463-5b86d302da89@huawei.com>
Date:   Tue, 30 Aug 2022 20:57:58 +0800
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Subject: Re: [PATCH] iommu: use iommu_group_ref_get to hold group reference
To:     Robin Murphy <robin.murphy@arm.com>, <joro@8bytes.org>,
        <will@kernel.org>, <iommu@lists.linux.dev>
CC:     <linux-kernel@vger.kernel.org>, <baolu.lu@linux.intel.com>,
        <haifeng.zhao@linux.intel.com>
References: <20220826024024.101553-1-yuancan@huawei.com>
 <5f47c5b7-534d-5714-1f91-04005ada8b8f@arm.com>
From:   Yuan Can <yuancan@huawei.com>
In-Reply-To: <5f47c5b7-534d-5714-1f91-04005ada8b8f@arm.com>
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在 2022/8/30 17:32, Robin Murphy 写道:
> On 2022-08-26 03:40, Yuan Can wrote:
>> Replace kobject_get with iommu_group_ref_get for better
>> readability.
>
> I disagree, sorry. iommu_group_ref_get() is meant as a helper for 
> drivers, and the core code uses the raw kobject internally everywhere 
> else, including several other times within this function. Especially 
> the raw kobject_put() in the cleanup path - in terms of readability 
> I'd say it's actively harmful to obfuscate what that pairs with.
>
> Thanks,
> Robin.

Understood, thanks for your reply.

Best regards,

Yuan Can

>
>> Signed-off-by: Yuan Can <yuancan@huawei.com>
>> ---
>>   drivers/iommu/iommu.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 780fb7071577..8e7f30f7188c 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -903,7 +903,7 @@ int iommu_group_add_device(struct iommu_group 
>> *group, struct device *dev)
>>           goto err_free_name;
>>       }
>>   -    kobject_get(group->devices_kobj);
>> +    iommu_group_ref_get(group);
>>         dev->iommu_group = group;
>