staging/vboxvideo: Refactor vbox_update_mode_hints

Refactor vbox_update_mode_hints to no longer use the obsolete
drm_modeset_lock_all() and switch it over to drm_connector_list_iter
instead of directly accessing the list using list_for_each_entry.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190304164724.10210-3-hdegoede@redhat.com

drivers/staging/vboxvideo/vbox_irq.c

@@ -105,6 +105,7 @@ static void validate_or_set_position_hints(struct vbox_private *vbox)
 /* Query the host for the most recent video mode hints. */
 static void vbox_update_mode_hints(struct vbox_private *vbox)
 {
+	struct drm_connector_list_iter conn_iter;
 	struct drm_device *dev = &vbox->ddev;
 	struct drm_connector *connector;
 	struct vbox_connector *vbox_conn;
@@ -122,13 +123,10 @@ static void vbox_update_mode_hints(struct vbox_private *vbox)
 	}
 
 	validate_or_set_position_hints(vbox);
-	drm_modeset_lock_all(dev);
-	/*
-	 * FIXME: this needs to use drm_connector_list_iter and some real
-	 * locking for the actual data it changes, not the deprecated
-	 * drm_modeset_lock_all() shotgun approach.
-	 */
-	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
 		vbox_conn = to_vbox_connector(connector);
 
 		hints = &vbox->last_mode_hints[vbox_conn->vbox_crtc->crtc_id];
@@ -157,7 +155,8 @@ static void vbox_update_mode_hints(struct vbox_private *vbox)
 
 		vbox_conn->vbox_crtc->disconnected = disconnected;
 	}
-	drm_modeset_unlock_all(dev);
+	drm_connector_list_iter_end(&conn_iter);
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
 }
 
 static void vbox_hotplug_worker(struct work_struct *work)