[Intel-gfx] [PATCH 1/2] drm/property: Enforce more lifetime rules

[Daniel Vetter]

Properties can't be attached after registering, userspace would get
confused (no one bothers to reprobe really).

- Add kerneldoc
- Enforce this with some checks. This needs a somewhat ugly check
  since connectors can be added later on, but we still need to attach
  all properties before they go public.

Note that we already enforce that properties themselves are created
before the entire device is registered.

Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Rajat Jain <rajatja at google.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/drm_mode_object.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c
index 6a23e36ed4fe..35c2719407a8 100644
--- a/drivers/gpu/drm/drm_mode_object.c
+++ b/drivers/gpu/drm/drm_mode_object.c
@@ -224,12 +224,26 @@ EXPORT_SYMBOL(drm_mode_object_get);
  * This attaches the given property to the modeset object with the given initial
  * value. Currently this function cannot fail since the properties are stored in
  * a statically sized array.
+ *
+ * Note that all properties must be attached before the object itself is
+ * registered and accessible from userspace.
  */
 void drm_object_attach_property(struct drm_mode_object *obj,
 				struct drm_property *property,
 				uint64_t init_val)
 {
 	int count = obj->properties->count;
+	struct drm_device *dev = property->dev;
+
+
+	if (obj->type == DRM_MODE_OBJECT_CONNECTOR) {
+		struct drm_connector *connector = obj_to_connector(obj);
+
+		WARN_ON(!dev->driver->load &&
+			connector->registration_state == DRM_CONNECTOR_REGISTERED);
+	} else {
+		WARN_ON(!dev->driver->load && dev->registered);
+	}
 
 	if (count == DRM_OBJECT_MAX_PROPERTY) {
 		WARN(1, "Failed to attach object property (type: 0x%x). Please "
-- 
2.23.0