drm: safely free connectors from connector_iter

[platform/kernel/linux-starfive.git] / drivers / gpu / drm / drm_connector.c

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 25f4b2e..4820141 100644 (file)
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -152,6 +152,16 @@ static void drm_connector_free(struct kref *kref)
        connector->funcs->destroy(connector);
 }
 
+static void drm_connector_free_work_fn(struct work_struct *work)
+{
+       struct drm_connector *connector =
+               container_of(work, struct drm_connector, free_work);
+       struct drm_device *dev = connector->dev;
+
+       drm_mode_object_unregister(dev, &connector->base);
+       connector->funcs->destroy(connector);
+}
+
 /**
  * drm_connector_init - Init a preallocated connector
  * @dev: DRM device
@@ -181,6 +191,8 @@ int drm_connector_init(struct drm_device *dev,
        if (ret)
                return ret;
 
+       INIT_WORK(&connector->free_work, drm_connector_free_work_fn);
+
        connector->base.properties = &connector->properties;
        connector->dev = dev;
        connector->funcs = funcs;
@@ -529,6 +541,18 @@ void drm_connector_list_iter_begin(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_connector_list_iter_begin);
 
+/*
+ * Extra-safe connector put function that works in any context. Should only be
+ * used from the connector_iter functions, where we never really expect to
+ * actually release the connector when dropping our final reference.
+ */
+static void
+drm_connector_put_safe(struct drm_connector *conn)
+{
+       if (refcount_dec_and_test(&conn->base.refcount.refcount))
+               schedule_work(&conn->free_work);
+}
+
 /**
  * drm_connector_list_iter_next - return next connector
  * @iter: connectr_list iterator
@@ -561,7 +585,7 @@ drm_connector_list_iter_next(struct drm_connector_list_iter *iter)
        spin_unlock_irqrestore(&config->connector_list_lock, flags);
 
        if (old_conn)
-               drm_connector_put(old_conn);
+               drm_connector_put_safe(old_conn);
 
        return iter->conn;
 }
@@ -580,7 +604,7 @@ void drm_connector_list_iter_end(struct drm_connector_list_iter *iter)
 {
        iter->dev = NULL;
        if (iter->conn)
-               drm_connector_put(iter->conn);
+               drm_connector_put_safe(iter->conn);
        lock_release(&connector_list_iter_dep_map, 0, _RET_IP_);
 }
 EXPORT_SYMBOL(drm_connector_list_iter_end);