drm/mode: move framebuffer reference into object.

This is the initial code to add references to some mode objects.
In the future we need to start reference counting connectors so
firstly I want to reorganise the code so the framebuffer ref counting
uses the same paths.

This patch shouldn't change any functionality, just moves the kref.

[airlied: move kerneldoc as well]
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_crtc.c

@@ -275,7 +275,8 @@ EXPORT_SYMBOL(drm_get_format_name);
 static int drm_mode_object_get_reg(struct drm_device *dev,
 				   struct drm_mode_object *obj,
 				   uint32_t obj_type,
-				   bool register_obj)
+				   bool register_obj,
+				   void (*obj_free_cb)(struct kref *kref))
 {
 	int ret;
 
@@ -288,6 +289,10 @@ static int drm_mode_object_get_reg(struct drm_device *dev,
 		 */
 		obj->id = ret;
 		obj->type = obj_type;
+		if (obj_free_cb) {
+			obj->free_cb = obj_free_cb;
+			kref_init(&obj->refcount);
+		}
 	}
 	mutex_unlock(&dev->mode_config.idr_mutex);
 
@@ -311,7 +316,7 @@ static int drm_mode_object_get_reg(struct drm_device *dev,
 int drm_mode_object_get(struct drm_device *dev,
 			struct drm_mode_object *obj, uint32_t obj_type)
 {
-	return drm_mode_object_get_reg(dev, obj, obj_type, true);
+	return drm_mode_object_get_reg(dev, obj, obj_type, true, NULL);
 }
 
 static void drm_mode_object_register(struct drm_device *dev,
@@ -389,10 +394,35 @@ struct drm_mode_object *drm_mode_object_find(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_mode_object_find);
 
+void drm_mode_object_unreference(struct drm_mode_object *obj)
+{
+	if (obj->free_cb) {
+		DRM_DEBUG("OBJ ID: %d (%d)\n", obj->id, atomic_read(&obj->refcount.refcount));
+		kref_put(&obj->refcount, obj->free_cb);
+	}
+}
+EXPORT_SYMBOL(drm_mode_object_unreference);
+
+/**
+ * drm_mode_object_reference - incr the fb refcnt
+ * @obj: mode_object
+ *
+ * This function operates only on refcounted objects.
+ * This functions increments the object's refcount.
+ */
+void drm_mode_object_reference(struct drm_mode_object *obj)
+{
+	if (obj->free_cb) {
+		DRM_DEBUG("OBJ ID: %d (%d)\n", obj->id, atomic_read(&obj->refcount.refcount));
+		kref_get(&obj->refcount);
+	}
+}
+EXPORT_SYMBOL(drm_mode_object_reference);
+
 static void drm_framebuffer_free(struct kref *kref)
 {
 	struct drm_framebuffer *fb =
-			container_of(kref, struct drm_framebuffer, refcount);
+			container_of(kref, struct drm_framebuffer, base.refcount);
 	struct drm_device *dev = fb->dev;
 
 	/*
@@ -430,12 +460,12 @@ int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb,
 	int ret;
 
 	mutex_lock(&dev->mode_config.fb_lock);
-	kref_init(&fb->refcount);
 	INIT_LIST_HEAD(&fb->filp_head);
 	fb->dev = dev;
 	fb->funcs = funcs;
 
-	ret = drm_mode_object_get(dev, &fb->base, DRM_MODE_OBJECT_FB);
+	ret = drm_mode_object_get_reg(dev, &fb->base, DRM_MODE_OBJECT_FB,
+				      true, drm_framebuffer_free);
 	if (ret)
 		goto out;
 
@@ -482,7 +512,7 @@ struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
 	mutex_lock(&dev->mode_config.fb_lock);
 	fb = __drm_framebuffer_lookup(dev, id);
 	if (fb) {
-		if (!kref_get_unless_zero(&fb->refcount))
+		if (!kref_get_unless_zero(&fb->base.refcount))
 			fb = NULL;
 	}
 	mutex_unlock(&dev->mode_config.fb_lock);
@@ -491,32 +521,6 @@ struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_framebuffer_lookup);
 
-/**
- * drm_framebuffer_unreference - unref a framebuffer
- * @fb: framebuffer to unref
- *
- * This functions decrements the fb's refcount and frees it if it drops to zero.
- */
-void drm_framebuffer_unreference(struct drm_framebuffer *fb)
-{
-	DRM_DEBUG("%p: FB ID: %d (%d)\n", fb, fb->base.id, atomic_read(&fb->refcount.refcount));
-	kref_put(&fb->refcount, drm_framebuffer_free);
-}
-EXPORT_SYMBOL(drm_framebuffer_unreference);
-
-/**
- * drm_framebuffer_reference - incr the fb refcnt
- * @fb: framebuffer
- *
- * This functions increments the fb's refcount.
- */
-void drm_framebuffer_reference(struct drm_framebuffer *fb)
-{
-	DRM_DEBUG("%p: FB ID: %d (%d)\n", fb, fb->base.id, atomic_read(&fb->refcount.refcount));
-	kref_get(&fb->refcount);
-}
-EXPORT_SYMBOL(drm_framebuffer_reference);
-
 /**
  * drm_framebuffer_unregister_private - unregister a private fb from the lookup idr
  * @fb: fb to unregister
@@ -902,7 +906,7 @@ int drm_connector_init(struct drm_device *dev,
 
 	drm_modeset_lock_all(dev);
 
-	ret = drm_mode_object_get_reg(dev, &connector->base, DRM_MODE_OBJECT_CONNECTOR, false);
+	ret = drm_mode_object_get_reg(dev, &connector->base, DRM_MODE_OBJECT_CONNECTOR, false, NULL);
 	if (ret)
 		goto out_unlock;
 
@@ -5971,7 +5975,7 @@ void drm_mode_config_cleanup(struct drm_device *dev)
 	 */
 	WARN_ON(!list_empty(&dev->mode_config.fb_list));
 	list_for_each_entry_safe(fb, fbt, &dev->mode_config.fb_list, head) {
-		drm_framebuffer_free(&fb->refcount);
+		drm_framebuffer_free(&fb->base.refcount);
 	}
 
 	ida_destroy(&dev->mode_config.connector_ida);

include/drm/drm_crtc.h

@@ -49,6 +49,8 @@ struct drm_mode_object {
 	uint32_t id;
 	uint32_t type;
 	struct drm_object_properties *properties;
+	struct kref refcount;
+	void (*free_cb)(struct kref *kref);
 };
 
 #define DRM_OBJECT_MAX_PROPERTY 24
@@ -223,8 +225,8 @@ struct drm_framebuffer {
 	 * should be deferred.  In cases like this, the driver would like to
 	 * hold a ref to the fb even though it has already been removed from
 	 * userspace perspective.
+	 * The refcount is stored inside the mode object.
 	 */
-	struct kref refcount;
 	/*
 	 * Place on the dev->mode_config.fb_list, access protected by
 	 * dev->mode_config.fb_lock.
@@ -2377,8 +2379,6 @@ extern int drm_framebuffer_init(struct drm_device *dev,
 				const struct drm_framebuffer_funcs *funcs);
 extern struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
 						      uint32_t id);
-extern void drm_framebuffer_unreference(struct drm_framebuffer *fb);
-extern void drm_framebuffer_reference(struct drm_framebuffer *fb);
 extern void drm_framebuffer_remove(struct drm_framebuffer *fb);
 extern void drm_framebuffer_cleanup(struct drm_framebuffer *fb);
 extern void drm_framebuffer_unregister_private(struct drm_framebuffer *fb);
@@ -2436,6 +2436,8 @@ extern int drm_mode_crtc_set_gamma_size(struct drm_crtc *crtc,
 					 int gamma_size);
 extern struct drm_mode_object *drm_mode_object_find(struct drm_device *dev,
 		uint32_t id, uint32_t type);
+void drm_mode_object_reference(struct drm_mode_object *obj);
+void drm_mode_object_unreference(struct drm_mode_object *obj);
 
 /* IOCTLs */
 extern int drm_mode_getresources(struct drm_device *dev,
@@ -2605,6 +2607,28 @@ static inline uint32_t drm_color_lut_extract(uint32_t user_input,
 	return clamp_val(val, 0, max);
 }
 
+/*
+ * drm_framebuffer_reference - incr the fb refcnt
+ * @fb: framebuffer
+ *
+ * This functions increments the fb's refcount.
+ */
+static inline void drm_framebuffer_reference(struct drm_framebuffer *fb)
+{
+	drm_mode_object_reference(&fb->base);
+}
+
+/**
+ * drm_framebuffer_unreference - unref a framebuffer
+ * @fb: framebuffer to unref
+ *
+ * This functions decrements the fb's refcount and frees it if it drops to zero.
+ */
+static inline void drm_framebuffer_unreference(struct drm_framebuffer *fb)
+{
+	drm_mode_object_unreference(&fb->base);
+}
+
 /**
  * drm_framebuffer_read_refcount - read the framebuffer reference count.
  * @fb: framebuffer
@@ -2613,7 +2637,7 @@ static inline uint32_t drm_color_lut_extract(uint32_t user_input,
  */
 static inline uint32_t drm_framebuffer_read_refcount(struct drm_framebuffer *fb)
 {
-	return atomic_read(&fb->refcount.refcount);
+	return atomic_read(&fb->base.refcount.refcount);
 }
 
 /* Plane list iterator for legacy (overlay only) planes. */