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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>, Robin Murphy <robin.murphy@arm.com>
Cc: baolu.lu@linux.intel.com, Christoph Hellwig <hch@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Kevin Tian <kevin.tian@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	kvm@vger.kernel.org, rafael@kernel.org,
	David Airlie <airlied@linux.ie>,
	linux-pci@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	Diana Craciun <diana.craciun@oss.nxp.com>,
	Dmitry Osipenko <digetx@gmail.com>, Will Deacon <will@kernel.org>,
	Stuart Yoder <stuyoder@gmail.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Cornelia Huck <cohuck@redhat.com>,
	linux-kernel@vger.kernel.org, Li Yang <leoyang.li@nxp.com>,
	iommu@lists.linux-foundation.org,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH v6 02/11] driver core: Add dma_cleanup callback in bus_type
Date: Tue, 22 Feb 2022 12:48:39 +0800	[thread overview]
Message-ID: <c212094a-399e-1038-99e0-7a08d0da2a61@linux.intel.com> (raw)
In-Reply-To: <20220221234837.GA10061@nvidia.com>

On 2/22/22 7:48 AM, Jason Gunthorpe wrote:
>> since we should only care about ownership at probe, hotplug, and other
>> places well outside critical fast-paths, I'm not sure we really need to keep
>> track of that anyway - it can always be recalculated by walking the
>> group->devices list,
> It has to be locked against concurrent probe, and there isn't
> currently any locking scheme that can support this. The owner_cnt is
> effectively a new lock for this purpose. It is the same issue we
> talked about with that VFIO patch you showed me.
> 
> So, using the group->device_list would require adding something else
> somewhere - which I think should happen when someone has
> justification for another use of whatever that something else is.

This series was originated from the similar idea by adding some fields
in driver structure and intercepting it in iommu core. We stopped doing
that due to the lack of lock mechanism between iommu and driver core.
It then evolved into what it is today.

Best regards,
baolu

  reply	other threads:[~2022-02-22  5:57 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-18  0:55 [PATCH v6 00/11] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu
2022-02-18  0:55 ` [PATCH v6 01/11] iommu: Add dma ownership management interfaces Lu Baolu
2022-02-19  7:31   ` Christoph Hellwig
2022-02-21  4:02     ` Lu Baolu
2022-02-23 18:00   ` Robin Murphy
2022-02-23 18:02     ` Jason Gunthorpe
2022-02-23 18:20       ` Robin Murphy
2022-02-23 18:32         ` Jason Gunthorpe
2022-02-24  5:16       ` Lu Baolu
2022-02-24  5:29         ` Lu Baolu
2022-02-24  8:58           ` Robin Murphy
2022-02-24  5:21     ` Lu Baolu
2022-02-18  0:55 ` [PATCH v6 02/11] driver core: Add dma_cleanup callback in bus_type Lu Baolu
2022-02-19  7:32   ` Christoph Hellwig
2022-02-21 20:43     ` Robin Murphy
2022-02-21 23:48       ` Jason Gunthorpe
2022-02-22  4:48         ` Lu Baolu [this message]
2022-02-22 10:58         ` Robin Murphy
2022-02-22 15:16           ` Jason Gunthorpe
2022-02-22 21:18             ` Robin Murphy
2022-02-22 23:53               ` Jason Gunthorpe
2022-02-23  5:01                 ` Lu Baolu
2022-02-23 13:04                   ` Robin Murphy
2022-02-23 13:46                     ` Jason Gunthorpe
2022-02-23 14:06                       ` Greg Kroah-Hartman
2022-02-23 14:09                         ` Jason Gunthorpe
2022-02-23 14:30                           ` Jason Gunthorpe
2022-02-23 16:03                             ` Greg Kroah-Hartman
2022-02-23 17:05                               ` Robin Murphy
2022-02-23 17:47                                 ` Greg Kroah-Hartman
2022-02-18  0:55 ` [PATCH v6 03/11] amba: Stop sharing platform_dma_configure() Lu Baolu
2022-02-18  0:55 ` [PATCH v6 04/11] bus: platform,amba,fsl-mc,PCI: Add device DMA ownership management Lu Baolu
2022-02-18  7:55   ` Greg Kroah-Hartman
2022-02-18  0:55 ` [PATCH v6 05/11] PCI: pci_stub: Set driver_managed_dma Lu Baolu
2022-02-18  0:55 ` [PATCH v6 06/11] PCI: portdrv: " Lu Baolu
2022-02-18  0:55 ` [PATCH v6 07/11] vfio: Set DMA ownership for VFIO devices Lu Baolu
2022-02-18  0:55 ` [PATCH v6 08/11] vfio: Remove use of vfio_group_viable() Lu Baolu
2022-02-18  0:55 ` [PATCH v6 09/11] vfio: Delete the unbound_list Lu Baolu
2022-02-18  0:55 ` [PATCH v6 10/11] vfio: Remove iommu group notifier Lu Baolu
2022-02-23 21:53   ` Alex Williamson
2022-02-24  2:49     ` Lu Baolu
2022-02-18  0:55 ` [PATCH v6 11/11] iommu: Remove iommu group changes notifier Lu Baolu
2022-02-18 15:51 ` [PATCH v6 00/11] Fix BUG_ON in vfio_iommu_group_notifier() Jason Gunthorpe
2022-02-21  3:38   ` Lu Baolu
2022-02-28  0:58 ` Lu Baolu

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