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Date:   Wed, 5 Apr 2023 09:15:12 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, iommu@lists.linux.dev,
        Robin Murphy <robin.murphy@arm.com>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>, dmaengine@vger.kernel.org,
        vkoul@kernel.org, Will Deacon <will@kernel.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Raj Ashok <ashok.raj@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>,
        "Yu, Fenghua" <fenghua.yu@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        "Zanussi, Tom" <tom.zanussi@intel.com>
Subject: Re: [PATCH v3 7/7] dmaengine/idxd: Re-enable kernel workqueue under
 DMA API
Message-ID: <ZC1mUKH/03QhkcR9@nvidia.com>
References: <20230331231137.1947675-1-jacob.jun.pan@linux.intel.com>
 <20230331231137.1947675-8-jacob.jun.pan@linux.intel.com>
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On Fri, Mar 31, 2023 at 04:11:37PM -0700, Jacob Pan wrote:
>  static void idxd_disable_system_pasid(struct idxd_device *idxd)
>  {
> +	struct pci_dev *pdev = idxd->pdev;
> +	struct device *dev = &pdev->dev;
> +	struct iommu_domain *domain;
> +	union gencfg_reg gencfg;
> +
> +	domain = iommu_get_domain_for_dev(dev);
> +	if (!domain || domain->type == IOMMU_DOMAIN_BLOCKED)
> +		return;
> +
> +	iommu_detach_device_pasid(domain, dev, idxd->pasid);

This sequence is kinda weird, we shouldn't pass in domain to
detach_device_pasid, IMHO. We already know the domain because we store
it in an xarray, it just creates weirdness if the user passes in the
wrong domain.

Jason