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From: Jason Gunthorpe <jgg@nvidia.com>
To: Baolu Lu <baolu.lu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>,
	Christoph Hellwig <hch@infradead.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.com>,
	Dave Jiang <dave.jiang@intel.com>, Vinod Koul <vkoul@kernel.org>,
	Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces
Date: Thu, 12 May 2022 08:51:36 -0300	[thread overview]
Message-ID: <20220512115136.GV49344@nvidia.com> (raw)
In-Reply-To: <05a68e1e-8e18-5914-ebe7-d7b1a4aaa2ec@linux.intel.com>

On Thu, May 12, 2022 at 11:02:39AM +0800, Baolu Lu wrote:
> > > +       mutex_lock(&group->mutex);
> > > +       domain = xa_load(&group->pasid_array, pasid);
> > > +       if (domain && domain->type != type)
> > > +               domain = NULL;
> > > +       mutex_unlock(&group->mutex);
> > > +       iommu_group_put(group);
> > > +
> > > +       return domain;
> > This is bad locking, group->pasid_array values cannot be taken outside
> > the lock.
> 
> It's not iommu core, but SVA (or other feature components) that manage
> the life cycle of a domain. The iommu core only provides a place to
> store the domain pointer. The feature components are free to fetch their
> domain pointers from iommu core as long as they are sure that the domain
> is alive during use.

I'm not convinced.

Jason

  parent reply	other threads:[~2022-05-12 11:51 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-10  6:17 [PATCH v6 00/12] iommu: SVA and IOPF refactoring Lu Baolu
2022-05-10  6:17 ` [PATCH v6 01/12] dmaengine: idxd: Separate user and kernel pasid enabling Lu Baolu
2022-05-10  6:17 ` [PATCH v6 02/12] iommu: Add pasid_bits field in struct dev_iommu Lu Baolu
2022-05-10 14:34   ` Jason Gunthorpe
2022-05-11  2:25     ` Baolu Lu
2022-05-11  8:00       ` Jean-Philippe Brucker
2022-05-11 11:59         ` Jason Gunthorpe
2022-05-10  6:17 ` [PATCH v6 03/12] iommu: Add attach/detach_dev_pasid domain ops Lu Baolu
2022-05-10 14:02   ` Jason Gunthorpe
2022-05-11  2:32     ` Baolu Lu
2022-05-11  4:09       ` Tian, Kevin
2022-05-11  7:54         ` Jean-Philippe Brucker
2022-05-11 12:02           ` Jason Gunthorpe
2022-05-12  7:00             ` Jean-Philippe Brucker
2022-05-12 11:51               ` Jason Gunthorpe
2022-05-16  2:03                 ` Baolu Lu
2022-05-10  6:17 ` [PATCH v6 04/12] iommu/sva: Basic data structures for SVA Lu Baolu
2022-05-10  6:17 ` [PATCH v6 05/12] iommu/vt-d: Remove SVM_FLAG_SUPERVISOR_MODE support Lu Baolu
2022-05-10 14:35   ` Jason Gunthorpe
2022-05-10  6:17 ` [PATCH v6 06/12] iommu/vt-d: Add SVA domain support Lu Baolu
2022-05-10  6:17 ` [PATCH v6 07/12] arm-smmu-v3/sva: " Lu Baolu
2022-05-10  6:17 ` [PATCH v6 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces Lu Baolu
2022-05-10 15:23   ` Jason Gunthorpe
2022-05-11  7:21     ` Baolu Lu
2022-05-11 14:53       ` Jason Gunthorpe
2022-05-12  3:02         ` Baolu Lu
2022-05-12  5:01           ` Tian, Kevin
2022-05-12  5:17             ` Baolu Lu
2022-05-12  5:44               ` Tian, Kevin
2022-05-12  6:16                 ` Baolu Lu
2022-05-12 11:48               ` Jason Gunthorpe
2022-05-12 11:59                 ` Baolu Lu
2022-05-12 12:03                   ` Jason Gunthorpe
2022-05-12 12:47                     ` Baolu Lu
2022-05-12 11:51           ` Jason Gunthorpe [this message]
2022-05-12 12:39             ` Baolu Lu
2022-05-10  6:17 ` [PATCH v6 09/12] iommu: Remove SVA related callbacks from iommu ops Lu Baolu
2022-05-10  6:17 ` [PATCH v6 10/12] iommu: Prepare IOMMU domain for IOPF Lu Baolu
2022-05-10  6:17 ` [PATCH v6 11/12] iommu: Per-domain I/O page fault handling Lu Baolu
2022-05-10  6:17 ` [PATCH v6 12/12] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu

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