Commit 25cde97d authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

iommufd: Move ioas related HWPT destruction into iommufd_hw_pagetable_destroy() 

A HWPT is permanently associated with an IOAS when it is created, remove
the strange situation where a refcount != 0 HWPT can have been
disconnected from the IOAS by putting all the IOAS related destruction in
the object destroy function.

Initializing a HWPT is two stages, we have to allocate it, attach it to a
device and then populate the domain. Once the domain is populated it is
fully linked to the IOAS.

Arrange things so that all the error unwinds flow through the
iommufd_hw_pagetable_destroy() and allow it to handle all cases.

Link: https://lore.kernel.org/r/4-v3-ae9c2975a131+2e1e8-iommufd_hwpt_jgg@nvidia.com


Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 342b9cab

drivers/iommu/iommufd/device.c

+2 −15
Original line number Diff line number Diff line
@@ -386,28 +386,19 @@ void iommufd_device_detach(struct iommufd_device *idev) 
{

	struct iommufd_hw_pagetable *hwpt = idev->hwpt;



	mutex_lock(&hwpt->ioas->mutex);

	mutex_lock(&hwpt->devices_lock);

	list_del(&idev->devices_item);

	if (!iommufd_hw_pagetable_has_group(hwpt, idev->group)) {

		if (list_empty(&hwpt->devices)) {

			iopt_table_remove_domain(&hwpt->ioas->iopt,

						 hwpt->domain);

			list_del(&hwpt->hwpt_item);

		}

	if (!iommufd_hw_pagetable_has_group(hwpt, idev->group))

		iommu_detach_group(hwpt->domain, idev->group);

	}

	iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev);

	idev->hwpt = NULL;

	mutex_unlock(&hwpt->devices_lock);

	mutex_unlock(&hwpt->ioas->mutex);



	if (hwpt->auto_domain)

		iommufd_object_destroy_user(idev->ictx, &hwpt->obj);

	else

		refcount_dec(&hwpt->obj.users);



	idev->hwpt = NULL;



	refcount_dec(&idev->obj.users);

}

EXPORT_SYMBOL_NS_GPL(iommufd_device_detach, IOMMUFD);
@@ -769,10 +760,6 @@ iommufd_device_selftest_attach(struct iommufd_ctx *ictx, 
void iommufd_device_selftest_detach(struct iommufd_ctx *ictx,

				    struct iommufd_hw_pagetable *hwpt)

{

	mutex_lock(&hwpt->ioas->mutex);

	iopt_table_remove_domain(&hwpt->ioas->iopt, hwpt->domain);

	list_del(&hwpt->hwpt_item);

	mutex_unlock(&hwpt->ioas->mutex);

	refcount_dec(&hwpt->obj.users);

}

#endif

drivers/iommu/iommufd/hw_pagetable.c

+19 −8
Original line number Diff line number Diff line
@@ -13,7 +13,17 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj) 


	WARN_ON(!list_empty(&hwpt->devices));



	if (!list_empty(&hwpt->hwpt_item)) {

		mutex_lock(&hwpt->ioas->mutex);

		list_del(&hwpt->hwpt_item);

		mutex_unlock(&hwpt->ioas->mutex);



		iopt_table_remove_domain(&hwpt->ioas->iopt, hwpt->domain);

	}



	if (hwpt->domain)

		iommu_domain_free(hwpt->domain);



	refcount_dec(&hwpt->ioas->obj.users);

	mutex_destroy(&hwpt->devices_lock);

}
@@ -37,21 +47,22 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas, 
	if (IS_ERR(hwpt))

		return hwpt;



	hwpt->domain = iommu_domain_alloc(dev->bus);

	if (!hwpt->domain) {

		rc = -ENOMEM;

		goto out_abort;

	}



	INIT_LIST_HEAD(&hwpt->devices);

	INIT_LIST_HEAD(&hwpt->hwpt_item);

	mutex_init(&hwpt->devices_lock);

	/* Pairs with iommufd_hw_pagetable_destroy() */

	refcount_inc(&ioas->obj.users);

	hwpt->ioas = ioas;



	hwpt->domain = iommu_domain_alloc(dev->bus);

	if (!hwpt->domain) {

		rc = -ENOMEM;

		goto out_abort;

	}



	return hwpt;



out_abort:

	iommufd_object_abort(ictx, &hwpt->obj);

	iommufd_object_abort_and_destroy(ictx, &hwpt->obj);

	return ERR_PTR(rc);

}