kernel/module.c: suppress warning about unused nowarn variable

This patch fix the following warning:
kernel/module.c: In function 'add_usage_links':
kernel/module.c:1653:6: warning: variable 'nowarn' set but not used [-Wunused-but-set-variable]

[jeyu: folded in first patch since it only swapped the function order
so that del_usage_links can be called from add_usage_links]
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
diff --git a/kernel/module.c b/kernel/module.c
index 3803449..f546d57 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1666,21 +1666,6 @@
 }
 #endif /* CONFIG_KALLSYMS */
 
-static void add_usage_links(struct module *mod)
-{
-#ifdef CONFIG_MODULE_UNLOAD
-	struct module_use *use;
-	int nowarn;
-
-	mutex_lock(&module_mutex);
-	list_for_each_entry(use, &mod->target_list, target_list) {
-		nowarn = sysfs_create_link(use->target->holders_dir,
-					   &mod->mkobj.kobj, mod->name);
-	}
-	mutex_unlock(&module_mutex);
-#endif
-}
-
 static void del_usage_links(struct module *mod)
 {
 #ifdef CONFIG_MODULE_UNLOAD
@@ -1693,6 +1678,26 @@
 #endif
 }
 
+static int add_usage_links(struct module *mod)
+{
+	int ret = 0;
+#ifdef CONFIG_MODULE_UNLOAD
+	struct module_use *use;
+
+	mutex_lock(&module_mutex);
+	list_for_each_entry(use, &mod->target_list, target_list) {
+		ret = sysfs_create_link(use->target->holders_dir,
+					&mod->mkobj.kobj, mod->name);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&module_mutex);
+	if (ret)
+		del_usage_links(mod);
+#endif
+	return ret;
+}
+
 static int module_add_modinfo_attrs(struct module *mod)
 {
 	struct module_attribute *attr;
@@ -1801,13 +1806,18 @@
 	if (err)
 		goto out_unreg_param;
 
-	add_usage_links(mod);
+	err = add_usage_links(mod);
+	if (err)
+		goto out_unreg_modinfo_attrs;
+
 	add_sect_attrs(mod, info);
 	add_notes_attrs(mod, info);
 
 	kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
 	return 0;
 
+out_unreg_modinfo_attrs:
+	module_remove_modinfo_attrs(mod);
 out_unreg_param:
 	module_param_sysfs_remove(mod);
 out_unreg_holders: