From: Jason Gunthorpe <jgg@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>,
Lu Baolu <baolu.lu@linux.intel.com>,
David Woodhouse <dwmw2@infradead.org>,
Heiko Stuebner <heiko@sntech.de>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Joerg Roedel <joro@8bytes.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-rockchip@lists.infradead.org"
<linux-rockchip@lists.infradead.org>,
"linux-sunxi@lists.linux.dev" <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 01/10] iommu: Remove useless group refcounting
Date: Fri, 21 Jul 2023 09:01:45 -0300 [thread overview]
Message-ID: <ZLpzqVAxxLGJp+L4@nvidia.com> (raw)
In-Reply-To: <BN9PR11MB5276130E7AE8B0BEA43FCC6C8C3FA@BN9PR11MB5276.namprd11.prod.outlook.com>
On Fri, Jul 21, 2023 at 07:10:57AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Wednesday, July 19, 2023 3:06 AM
> >
> > int iommu_device_use_default_domain(struct device *dev)
> > {
> > - struct iommu_group *group = iommu_group_get(dev);
> > + /* Caller must be a probed driver on dev */
> > + struct iommu_group *group = dev->iommu_group;
> > int ret = 0;
>
> this is called in the probing path by .dma_configure().
>
> the driver hasn't been probed yet hence the rationale to not
> refcount is due to device_lock() instead?
At this point the driver core has partially attached/detached a driver
so I'm considering it part of the probed driver explanation.
Really during anything protected by the driver core probe path is
assured that the group cannot change.
Jason
next prev parent reply other threads:[~2023-07-21 12:01 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-18 19:05 [PATCH 00/10] Refine the locking for dev->iommu_group Jason Gunthorpe
2023-07-18 19:05 ` [PATCH 01/10] iommu: Remove useless group refcounting Jason Gunthorpe
2023-07-20 6:11 ` Baolu Lu
2023-07-21 7:10 ` Tian, Kevin
2023-07-21 12:01 ` Jason Gunthorpe [this message]
2023-07-24 2:11 ` Tian, Kevin
2023-07-24 18:06 ` Jason Gunthorpe
2023-07-25 2:12 ` Tian, Kevin
2023-07-18 19:05 ` [PATCH 02/10] iommu: Add a lockdep assertion for remaining dev->iommu_group reads Jason Gunthorpe
2023-07-20 6:33 ` Baolu Lu
2023-07-18 19:05 ` [PATCH 03/10] iommu: Add generic_single_device_group() Jason Gunthorpe
2023-07-20 7:39 ` Baolu Lu
2023-07-20 12:04 ` Jason Gunthorpe
2023-07-20 14:01 ` Baolu Lu
2023-07-21 17:19 ` Jason Gunthorpe
2023-07-22 14:01 ` Baolu Lu
2023-07-21 7:17 ` Tian, Kevin
2023-07-24 13:15 ` Jason Gunthorpe
2023-07-22 14:02 ` Baolu Lu
2023-07-18 19:05 ` [PATCH 04/10] iommu/sun50i: Convert to generic_single_device_group() Jason Gunthorpe
2023-07-18 19:05 ` [PATCH 05/10] iommu/sprd: " Jason Gunthorpe
2023-07-18 19:05 ` [PATCH 06/10] iommu/rockchip: " Jason Gunthorpe
2023-07-18 19:05 ` [PATCH 07/10] iommu/ipmmu-vmsa: " Jason Gunthorpe
2023-07-21 7:20 ` Tian, Kevin
2023-07-21 12:04 ` Jason Gunthorpe
2023-07-18 19:05 ` [PATCH 08/10] iommu/omap: " Jason Gunthorpe
2023-07-18 19:05 ` [PATCH 09/10] iommu: Complete the locking for dev->iommu_group Jason Gunthorpe
2023-07-20 9:55 ` Baolu Lu
2023-07-18 19:05 ` [PATCH 10/10] iommu/intel: Fix missing locking for show_device_domain_translation() Jason Gunthorpe
2023-07-20 9:56 ` Baolu Lu
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