cgroup-util: use string_hash_ops_free

src/basic/cgroup-util.c

@@ -2001,7 +2001,7 @@ int cg_mask_supported(CGroupMask *ret) {
 }
 
 int cg_kernel_controllers(Set **ret) {
-        _cleanup_set_free_free_ Set *controllers = NULL;
+        _cleanup_set_free_ Set *controllers = NULL;
         _cleanup_fclose_ FILE *f = NULL;
         int r;
 
@@ -2011,10 +2011,6 @@ int cg_kernel_controllers(Set **ret) {
          * and controllers that aren't currently accessible (because not mounted). This does not include "name="
          * pseudo-controllers. */
 
-        controllers = set_new(&string_hash_ops);
-        if (!controllers)
-                return -ENOMEM;
-
         r = fopen_unlocked("/proc/cgroups", "re", &f);
         if (r == -ENOENT) {
                 *ret = NULL;
@@ -2048,7 +2044,7 @@ int cg_kernel_controllers(Set **ret) {
                 if (!cg_controller_is_valid(controller))
                         return -EBADMSG;
 
-                r = set_consume(controllers, TAKE_PTR(controller));
+                r = set_ensure_consume(&controllers, &string_hash_ops_free, TAKE_PTR(controller));
                 if (r < 0)
                         return r;
         }