Now, iommufd has its own iommufd_sw_msi using iommufd_hwpt, the iommufd
owned domain's private pointer. Similarly, iova_cookie can be seen as a
dma-iommu owned domain's private pointer. So, move iova_cookie into the
union.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 include/linux/iommu.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index b6526d734f30..284c40fe0e12 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -216,7 +216,6 @@ struct iommu_domain {
 	const struct iommu_ops *owner; /* Whose domain_alloc we came from */
 	unsigned long pgsize_bitmap;	/* Bitmap of page sizes in use */
 	struct iommu_domain_geometry geometry;
-	struct iommu_dma_cookie *iova_cookie;
 	int (*iopf_handler)(struct iopf_group *group);
 
 #if IS_ENABLED(CONFIG_IRQ_MSI_IOMMU)
@@ -225,6 +224,7 @@ struct iommu_domain {
 #endif
 
 	union { /* Pointer usable by owner of the domain */
+		struct iommu_dma_cookie *iova_cookie; /* dma-iommu */
 		struct iommufd_hw_pagetable *iommufd_hwpt; /* iommufd */
 	};
 	union { /* Fault handler */
-- 
2.43.0

On Fri, Jan 10, 2025 at 07:32:24PM -0800, Nicolin Chen wrote:
> Now, iommufd has its own iommufd_sw_msi using iommufd_hwpt, the iommufd
> owned domain's private pointer. Similarly, iova_cookie can be seen as a
> dma-iommu owned domain's private pointer. So, move iova_cookie into the
> union.

This commit message would be clearer as:

Now that iommufd does not rely on dma-iommu.c for any purpose we can
combine the dma-iommu.c iova_cookie and the iommufd_hwpt under the
same union. This union is effectively 'owner data' can be used by the
entity that allocated the domain. Note that legacy vfio type1 flows
continue to use dma-iommu.c for sw_msi and still need iova_cookie.

Jason