diff --git a/src/util/virmacmap.c b/src/util/virmacmap.c
index 88ca9b3f36..c7b700fa05 100644
--- a/src/util/virmacmap.c
+++ b/src/util/virmacmap.c
@@ -90,7 +90,6 @@ virMacMapAddLocked(virMacMapPtr mgr,
 {
     int ret = -1;
     char **macsList = NULL;
-    char **newMacsList = NULL;
 
     if ((macsList = virHashLookup(mgr->macs, domain)) &&
         virStringListHasString((const char**) macsList, mac)) {
@@ -98,15 +97,12 @@ virMacMapAddLocked(virMacMapPtr mgr,
         goto cleanup;
     }
 
-    if (!(newMacsList = virStringListAdd((const char **) macsList, mac)) ||
-        virHashUpdateEntry(mgr->macs, domain, newMacsList) < 0)
+    if (virStringListAdd(&macsList, mac) < 0 ||
+        virHashUpdateEntry(mgr->macs, domain, macsList) < 0)
         goto cleanup;
-    newMacsList = NULL;
-    virStringListFree(macsList);
 
     ret = 0;
  cleanup:
-    virStringListFree(newMacsList);
     return ret;
 }
 
diff --git a/src/util/virstring.c b/src/util/virstring.c
index 93fda69d7f..afad5736e1 100644
--- a/src/util/virstring.c
+++ b/src/util/virstring.c
@@ -175,32 +175,23 @@ char *virStringListJoin(const char **strings,
  * @strings: a NULL-terminated array of strings
  * @item: string to add
  *
- * Creates new strings list with all strings duplicated and @item
- * at the end of the list. Callers is responsible for freeing
- * both @strings and returned list.
+ * Appends @item into string list @strings. If *@strings is not
+ * allocated yet new string list is created.
+ *
+ * Returns: 0 on success,
+ *         -1 otherwise
  */
-char **
-virStringListAdd(const char **strings,
+int
+virStringListAdd(char ***strings,
                  const char *item)
 {
-    char **ret = NULL;
-    size_t i = virStringListLength(strings);
+    size_t i = virStringListLength((const char **) *strings);
 
-    if (VIR_ALLOC_N(ret, i + 2) < 0)
-        goto error;
+    if (VIR_EXPAND_N(*strings, i, 2) < 0 ||
+        VIR_STRDUP((*strings)[i - 2], item) < 0)
+        return -1;
 
-    for (i = 0; strings && strings[i]; i++) {
-        if (VIR_STRDUP(ret[i], strings[i]) < 0)
-            goto error;
-    }
-
-    if (VIR_STRDUP(ret[i], item) < 0)
-        goto error;
-
-    return ret;
- error:
-    virStringListFree(ret);
-    return NULL;
+    return 0;
 }
 
 
diff --git a/src/util/virstring.h b/src/util/virstring.h
index 125fd4eede..a2133ab7ce 100644
--- a/src/util/virstring.h
+++ b/src/util/virstring.h
@@ -44,8 +44,8 @@ char *virStringListJoin(const char **strings,
                         const char *delim)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
 
-char **virStringListAdd(const char **strings,
-                        const char *item);
+int virStringListAdd(char ***strings,
+                     const char *item);
 void virStringListRemove(char ***strings,
                          const char *item);
 
diff --git a/tests/virstringtest.c b/tests/virstringtest.c
index 1230aba5b7..1a1e6364d1 100644
--- a/tests/virstringtest.c
+++ b/tests/virstringtest.c
@@ -179,12 +179,8 @@ static int testAdd(const void *args)
     size_t i;
 
     for (i = 0; data->tokens[i]; i++) {
-        char **tmp = virStringListAdd((const char **)list, data->tokens[i]);
-        if (!tmp)
+        if (virStringListAdd(&list, data->tokens[i]) < 0)
             goto cleanup;
-        virStringListFree(list);
-        list = tmp;
-        tmp = NULL;
     }
 
     if (!list &&