diff --git a/core/includes/update.inc b/core/includes/update.inc
index 343d980..e277660 100644
--- a/core/includes/update.inc
+++ b/core/includes/update.inc
@@ -1044,6 +1044,9 @@ function update_variable_del($name) {
  *   @endcode
  *   This would migrate the value contained in variable name 'old_variable' into
  *   the data key 'new_config.sub_key' of the configuration object $config_name.
+ * @param string $default_config_name
+ *   The name of the configuration object to copy data from if $config_name
+ *   does not yet exist.
  */
 function update_variables_to_config($config_name, array $variable_map, $default_config_name = NULL) {
   // Build the new configuration object.
@@ -1057,16 +1060,14 @@ function update_variables_to_config($config_name, array $variable_map, $default_
 
   // Load and set default configuration values.
   $file = new FileStorage(drupal_get_path('module', $module) . '/config');
-  if (!$file->exists($config_name)) {
-    if ($default_config_name && $file->exists($default_config_name)) {
-      $default_data = $file->read($default_config_name);
-    }
-    else {
-      throw new ConfigException("Default configuration file $config_name for $module extension not found but is required to exist.");
-    }
+  if ($file->exists($config_name)) {
+    $default_data = $file->read($config_name);
+  }
+  elseif ($default_config_name && $file->exists($default_config_name)) {
+    $default_data = $file->read($default_config_name);
   }
   else {
-    $default_data = $file->read($config_name);
+    throw new ConfigException("Default configuration file $config_name for $module extension not found but is required to exist.");
   }
   // Merge any possibly existing original data into default values.
   // Only relevant when being called repetitively on the same config object.
diff --git a/core/modules/comment/comment.install b/core/modules/comment/comment.install
index bb0ddc2..068e53c 100644
--- a/core/modules/comment/comment.install
+++ b/core/modules/comment/comment.install
@@ -13,19 +13,11 @@ function comment_uninstall() {
   field_delete_field('comment_body');
 
   // Remove variables.
-  config('comment.settings')->clear('comment_block_count');
+  config('comment.settings')->delete();
   $node_types = array_keys(node_type_get_types());
   foreach ($node_types as $node_type) {
     field_attach_delete_bundle('comment', 'comment_node_' . $node_type);
-    config('comment.settings.' . $node_type)->clear('comment');
-    config('comment.settings.' . $node_type)->clear('comment_anonymous');
-    config('comment.settings.' . $node_type)->clear('comment_controls');
-    config('comment.settings.' . $node_type)->clear('comment_default_mode');
-    config('comment.settings.' . $node_type)->clear('comment_default_order');
-    config('comment.settings.' . $node_type)->clear('comment_default_per_page');
-    config('comment.settings.' . $node_type)->clear('comment_form_location');
-    config('comment.settings.' . $node_type)->clear('comment_preview');
-    config('comment.settings.' . $node_type)->clear('comment_subject_field');
+    config('comment.settings.' . $node_type)->delete();
   }
 }
 
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index af69ce4..882dbd4 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -189,7 +189,7 @@ function comment_field_extra_fields() {
   $return = array();
 
   foreach (node_type_get_types() as $type) {
-    if (config('comment.settings.' . $type->type)->get('comment_subject_field') == 1) {
+    if (config('comment.settings.' . $type->type)->get('comment_subject_field')) {
       $return['comment']['comment_node_' . $type->type] = array(
         'form' => array(
           'author' => array(
@@ -471,7 +471,9 @@ function comment_block_configure($delta = '') {
  * Implements hook_block_save().
  */
 function comment_block_save($delta = '', $edit = array()) {
-  config('comment.settings')->set('comment_block_count', $edit['comment_block_count'])->save();
+  config('comment.settings')
+    ->set('comment_block_count', $edit['comment_block_count'])
+    ->save();
 }
 
 /**
@@ -566,8 +568,9 @@ function comment_get_recent($number = 10) {
  *   "page=X" if the page number is greater than zero; empty string otherwise.
  */
 function comment_new_page_count($num_comments, $new_replies, Node $node) {
-  $mode = config('comment.settings.' . $node->type)->get('comment_default_mode');
-  $comments_per_page = config('comment.settings.' . $node->type)->get('comment_default_per_page');
+  $config = config('comment.settings.' . $node->type);
+  $mode = $config->get('comment_default_mode');
+  $comments_per_page = $config->get('comment_default_per_page');
   $pagenum = NULL;
   $flat = $mode == COMMENT_MODE_FLAT ? TRUE : FALSE;
   if ($num_comments <= $comments_per_page) {
@@ -1276,7 +1279,6 @@ function comment_submit_config($form, &$form_state) {
     ->set('comment_form_location', $form_state['values']['comment_form_location'])
     ->set('comment_preview', $form_state['values']['comment_preview'])
     ->save();
-  watchdog('comment', 'CMI configuration variables updated for node type %type', array('%type' => $form['#node_type']->type));
 }
 
 /**
diff --git a/core/modules/comment/lib/Drupal/comment/CommentFormController.php b/core/modules/comment/lib/Drupal/comment/CommentFormController.php
index 52dd739..69888f5 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentFormController.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentFormController.php
@@ -159,7 +159,7 @@ class CommentFormController extends EntityFormController {
       '#title' => t('Subject'),
       '#maxlength' => 64,
       '#default_value' => $comment->subject,
-      '#access' => config('comment.settings.' . $node->type)->get('comment_subject_field') == 1,
+      '#access' => config('comment.settings.' . $node->type)->get('comment_subject_field'),
     );
 
     // Used for conditional validation of author fields.