[PATCH v5 03/13] iommufd: Add iommufd_verify_unfinalized_object

[Nicolin Chen]

To support driver-allocated vIOMMU objects, it's suggested to call the
allocator helper in IOMMU dirvers. However, there is no guarantee that
drivers will all use it and allocate objects properly.

Add a helper for iommufd core to verify if an unfinalized object is at
least reserved in the ictx.

Reviewed-by: Kevin Tian <kevin.t...@intel.com>
Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h |  3 +++
 drivers/iommu/iommufd/main.c            | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/drivers/iommu/iommufd/iommufd_private.h 
b/drivers/iommu/iommufd/iommufd_private.h
index 5bd41257f2ef..d53c1ca75532 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -152,6 +152,9 @@ static inline void iommufd_put_object(struct iommufd_ctx 
*ictx,
                wake_up_interruptible_all(&ictx->destroy_wait);
 }
 
+int iommufd_verify_unfinalized_object(struct iommufd_ctx *ictx,
+                                     struct iommufd_object *to_verify);
+
 void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object 
*obj);
 void iommufd_object_abort_and_destroy(struct iommufd_ctx *ictx,
                                      struct iommufd_object *obj);
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 92bd075108e5..e244fed1b7ab 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -89,6 +89,26 @@ struct iommufd_object *iommufd_get_object(struct iommufd_ctx 
*ictx, u32 id,
        return obj;
 }
 
+int iommufd_verify_unfinalized_object(struct iommufd_ctx *ictx,
+                                     struct iommufd_object *to_verify)
+{
+       XA_STATE(xas, &ictx->objects, 0);
+       struct iommufd_object *obj;
+       int rc = 0;
+
+       if (!to_verify || !to_verify->id)
+               return -EINVAL;
+       xas.xa_index = to_verify->id;
+
+       xa_lock(&ictx->objects);
+       obj = xas_load(&xas);
+       /* Being an unfinalized object, the loaded obj is a reserved space */
+       if (obj != XA_ZERO_ENTRY)
+               rc = -ENOENT;
+       xa_unlock(&ictx->objects);
+       return rc;
+}
+
 static int iommufd_object_dec_wait_shortterm(struct iommufd_ctx *ictx,
                                             struct iommufd_object *to_destroy)
 {
-- 
2.43.0