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From: Jason Gunthorpe <jgg@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: "iommu@lists.linux.dev" <iommu@lists.linux.dev>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Nicolin Chen <nicolinc@nvidia.com>,
	"Liu, Yi L" <yi.l.liu@intel.com>
Subject: Re: [PATCH v3 10/17] iommufd: Reorganize iommufd_device_attach into iommufd_device_change_pt
Date: Thu, 23 Mar 2023 11:26:08 -0300	[thread overview]
Message-ID: <ZBxhgP6xzI9bbjXq@nvidia.com> (raw)
In-Reply-To: <BN9PR11MB52765C5992F59307F24635058C879@BN9PR11MB5276.namprd11.prod.outlook.com>

On Thu, Mar 23, 2023 at 07:25:55AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Wednesday, March 22, 2023 3:15 AM
> > +int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
> > +{
> > +	int rc;
> > +
> > +	rc = iommufd_device_change_pt(idev, pt_id,
> > &iommufd_device_do_attach);
> > +	if (rc)
> > +		return rc;
> > +
> > +	/*
> > +	 * Pairs with iommufd_device_detach() - catches caller bugs
> > attempting
> > +	 * to destroy a device with an attachment.
> > +	 */
> > +	refcount_inc(&idev->obj.users);
> > +	return 0;
> 
> While it's the right thing to do I'm not sure what "catch caller bugs"
> mean here. There is no WARN_ON to catch.

The WARN_ON is on the destroy path of the device

	was_destroyed = iommufd_object_destroy_user(idev->ictx, &idev->obj);
	WARN_ON(!was_destroyed);

It is the idev we are incr'ing

Jason

  reply	other threads:[~2023-03-23 14:26 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-21 19:14 [PATCH v3 00/17] Add iommufd physical device operations for replace and alloc hwpt Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 01/17] iommufd: Move isolated msi enforcement to iommufd_device_bind() Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 02/17] iommufd: Add iommufd_group Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 03/17] iommufd: Replace the hwpt->devices list with iommufd_group Jason Gunthorpe
2023-03-23  7:21   ` Tian, Kevin
2023-03-23 14:23     ` Jason Gunthorpe
2023-03-24  1:37       ` Tian, Kevin
2023-03-24 15:02         ` Jason Gunthorpe
2023-03-28  2:32           ` Tian, Kevin
2023-03-28 11:38             ` Jason Gunthorpe
2023-03-29  3:03               ` Tian, Kevin
2023-04-11 14:31     ` Jason Gunthorpe
2023-04-12  8:27       ` Tian, Kevin
2023-04-12 11:17         ` Jason Gunthorpe
2023-04-13  2:52           ` Tian, Kevin
2023-04-14 13:31             ` Jason Gunthorpe
2023-04-20  6:15               ` Tian, Kevin
2023-04-20 15:34                 ` Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 04/17] iommu: Export iommu_get_resv_regions() Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 05/17] iommufd: Keep track of each device's reserved regions instead of groups Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 06/17] iommufd: Use the iommufd_group to avoid duplicate MSI setup Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 07/17] iommufd: Make sw_msi_start a group global Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 08/17] iommufd: Move putting a hwpt to a helper function Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 09/17] iommufd: Add enforced_cache_coherency to iommufd_hw_pagetable_alloc() Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 10/17] iommufd: Reorganize iommufd_device_attach into iommufd_device_change_pt Jason Gunthorpe
2023-03-23  7:25   ` Tian, Kevin
2023-03-23 14:26     ` Jason Gunthorpe [this message]
2023-03-21 19:14 ` [PATCH v3 11/17] iommu: Introduce a new iommu_group_replace_domain() API Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 12/17] iommufd: Add iommufd_device_replace() Jason Gunthorpe
2023-03-23  7:31   ` Tian, Kevin
2023-03-23 14:30     ` Jason Gunthorpe
2023-03-24  1:42       ` Tian, Kevin
2023-03-24 15:03         ` Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 13/17] iommufd: Make destroy_rwsem use a lock class per object type Jason Gunthorpe
2023-03-23  7:54   ` Tian, Kevin
2023-03-21 19:14 ` [PATCH v3 14/17] iommufd/selftest: Test iommufd_device_replace() Jason Gunthorpe
2023-03-23  7:57   ` Tian, Kevin
2023-03-23 14:32     ` Jason Gunthorpe
2023-03-21 19:14 ` [PATCH v3 15/17] iommufd: Add IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-03-23  8:00   ` Tian, Kevin
2023-03-21 19:14 ` [PATCH v3 16/17] iommufd/selftest: Return the real idev id from selftest mock_domain Jason Gunthorpe
2023-03-23  8:02   ` Tian, Kevin
2023-03-21 19:14 ` [PATCH v3 17/17] iommufd/selftest: Add a selftest for IOMMU_HWPT_ALLOC Jason Gunthorpe
2023-03-23  8:03   ` Tian, Kevin
2023-03-23  8:04 ` [PATCH v3 00/17] Add iommufd physical device operations for replace and alloc hwpt Tian, Kevin
2023-03-23 14:35   ` Jason Gunthorpe

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