[PATCH v6 04/10] iommufd: Reserve all negative IDs in the iommufd xarray

Yi Liu
2023-05-22T11:58:14Z

With this reservation, IOMMUFD users can encode the negative IDs for
specific purposes. e.g. VFIO needs two reserved values to tell userspace
the ID returned is not valid but has other meaning.

Tested-by: Terrence Xu <terrence.xu@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/iommu/iommufd/main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 3fbe636c3d8a..32ce7befc8dd 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -50,7 +50,7 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx,
* before calling iommufd_object_finalize().
*/
rc = xa_alloc(&ictx->objects, &obj->id, XA_ZERO_ENTRY,
- xa_limit_32b, GFP_KERNEL_ACCOUNT);
+ xa_limit_31b, GFP_KERNEL_ACCOUNT);
if (rc)
goto out_free;
return obj;
--
2.34.1