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Message-ID: <1122d8bf-b10f-9376-e103-5fa9a0cba561@linux.intel.com>
Date: Sat, 22 Jul 2023 22:01:04 +0800
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Cc: baolu.lu@linux.intel.com, Baolin Wang <baolin.wang@linux.alibaba.com>,
 David Woodhouse <dwmw2@infradead.org>, Heiko Stuebner <heiko@sntech.de>,
 iommu@lists.linux.dev, Jernej Skrabec <jernej.skrabec@gmail.com>,
 Joerg Roedel <joro@8bytes.org>, linux-arm-kernel@lists.infradead.org,
 linux-rockchip@lists.infradead.org, linux-sunxi@lists.linux.dev,
 Orson Zhai <orsonzhai@gmail.com>, Robin Murphy <robin.murphy@arm.com>,
 Samuel Holland <samuel@sholland.org>, Chen-Yu Tsai <wens@csie.org>,
 Will Deacon <will@kernel.org>, Chunyan Zhang <zhang.lyra@gmail.com>,
 Alex Williamson <alex.williamson@redhat.com>
Subject: Re: [PATCH 03/10] iommu: Add generic_single_device_group()
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To: Jason Gunthorpe <jgg@nvidia.com>
References: <3-v1-3c8177327a47+256-iommu_group_locking_jgg@nvidia.com>
 <32eadc5b-bb39-5bb1-f124-44feead97ce9@linux.intel.com>
 <ZLkiu7IyimCckiFs@nvidia.com>
 <c98c37bb-57c5-faec-1d17-730f3ceb2b21@linux.intel.com>
 <ZLq+PzR57D+RN2JF@nvidia.com>
From: Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <ZLq+PzR57D+RN2JF@nvidia.com>
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On 2023/7/22 1:19, Jason Gunthorpe wrote:
> On Thu, Jul 20, 2023 at 10:01:54PM +0800, Baolu Lu wrote:
> 
>> Then, another small comment:
>>
>> iommu->singleton_group will be freed with above put, right? Do you need
>> to set iommu->singleton_group to NULL? Given that iommu_device is not
>> freed here.
> Well, I think the general API is we expect the caller to free the
> iommu_device after calling unregister so this would be like all the
> other places we free or put something then go on to release the
> memory.
> 
> At the very least if the caller thinks it should re-use the
> iommu_device then it needs to zero it.
> 
> Notice this also doesn't hold the lock while putting it, we require no
> concurrent calls to probe with unregister.

Fair enough. Thanks for the explanation.

Best regards,
baolu