iommufd: Allow passing in iopt_access_list_id to iopt_remove_access()

This is a preparatory change for ioas replacement support for accesses.
The replacement routine does an iopt_add_access() for a new IOAS first and
then iopt_remove_access() for the old IOAS upon the success of the first
call. However, the first call overrides the iopt_access_list_id in the
access struct, resulting in iopt_remove_access() being unable to work on
the old IOAS.

Add an iopt_access_list_id as a parameter to iopt_remove_access, so the
replacement routine can save the id before it gets overwritten. Pass the
id in iopt_remove_access() for a proper cleanup.

The existing callers should just pass in access->iopt_access_list_id.

Link: https://lore.kernel.org/r/7bb939b9e0102da0c099572bb3de78ab7622221e.1690523699.git.nicolinc@nvidia.comSuggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/iommu/iommufd/device.c

@@ -690,7 +690,8 @@ void iommufd_access_destroy_object(struct iommufd_object *obj)
 		container_of(obj, struct iommufd_access, obj);
 
 	if (access->ioas) {
-		iopt_remove_access(&access->ioas->iopt, access);
+		iopt_remove_access(&access->ioas->iopt, access,
+				   access->iopt_access_list_id);
 		refcount_dec(&access->ioas->obj.users);
 		access->ioas = NULL;
 	}
@@ -776,7 +777,8 @@ void iommufd_access_detach(struct iommufd_access *access)
 		access->ops->unmap(access->data, 0, ULONG_MAX);
 		mutex_lock(&access->ioas_lock);
 	}
-	iopt_remove_access(&cur_ioas->iopt, access);
+	iopt_remove_access(&cur_ioas->iopt, access,
+			   access->iopt_access_list_id);
 	refcount_dec(&cur_ioas->obj.users);
 out:
 	access->ioas_unpin = NULL;

drivers/iommu/iommufd/io_pagetable.c

@@ -1158,12 +1158,12 @@ int iopt_add_access(struct io_pagetable *iopt, struct iommufd_access *access)
 }
 
 void iopt_remove_access(struct io_pagetable *iopt,
-			struct iommufd_access *access)
+			struct iommufd_access *access,
+			u32 iopt_access_list_id)
 {
 	down_write(&iopt->domains_rwsem);
 	down_write(&iopt->iova_rwsem);
-	WARN_ON(xa_erase(&iopt->access_list, access->iopt_access_list_id) !=
-		access);
+	WARN_ON(xa_erase(&iopt->access_list, iopt_access_list_id) != access);
 	WARN_ON(iopt_calculate_iova_alignment(iopt));
 	up_write(&iopt->iova_rwsem);
 	up_write(&iopt->domains_rwsem);

drivers/iommu/iommufd/iommufd_private.h

@@ -323,7 +323,8 @@ struct iommufd_access {
 
 int iopt_add_access(struct io_pagetable *iopt, struct iommufd_access *access);
 void iopt_remove_access(struct io_pagetable *iopt,
-			struct iommufd_access *access);
+			struct iommufd_access *access,
+			u32 iopt_access_list_id);
 void iommufd_access_destroy_object(struct iommufd_object *obj);
 
 #ifdef CONFIG_IOMMUFD_TEST