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[142.68.128.5]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6cc2291dbd5sm28380436d6.50.2024.10.17.06.39.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Oct 2024 06:39:19 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1t1Qik-003yqY-LN; Thu, 17 Oct 2024 10:39:18 -0300 Date: Thu, 17 Oct 2024 10:39:18 -0300 From: Jason Gunthorpe To: Vasant Hegde Cc: iommu@lists.linux.dev, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, suravee.suthikulpanit@amd.com, Joerg Roedel Subject: Re: [PATCH v3 10/10] iommu/amd: Improve amd_iommu_release_device() Message-ID: <20241017133918.GT4020792@ziepe.ca> References: <20241016053501.97497-1-vasant.hegde@amd.com> <20241016053501.97497-11-vasant.hegde@amd.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241016053501.97497-11-vasant.hegde@amd.com> On Wed, Oct 16, 2024 at 05:35:01AM +0000, Vasant Hegde wrote: > @@ -2251,7 +2234,18 @@ static void amd_iommu_release_device(struct device *dev) > if (!iommu) > return; > > - amd_iommu_uninit_device(dev); > + dev_data = dev_iommu_priv_get(dev); > + if (!dev_data) > + return; This can never happen, the core code never calls an op unless probe_device succeeded. > + if (dev_data->domain) > + detach_device(dev); This is also can't happen. The driver sets release_domain then the core code never calls this with anything other than release_domain attached. Suggest just struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev); WARN_ON(dev->data->domain); > + /* > + * We keep dev_data around for unplugged devices and reuse it when the > + * device is re-plugged - not doing so would introduce a ton of races. > + */ > + Yikes.. Sounds sketchy. Why doesn't any other driver have these races? Jason