Merge pull request #75264 from smarterclayton/optimize_rbac_visit

Avoid allocating when performing VisitRulesFor on service accounts

pkg/registry/rbac/validation/rule.go

@@ -286,7 +286,8 @@ func appliesToUser(user user.Info, subject rbacv1.Subject, namespace string) boo
 		if len(saNamespace) == 0 {
 			return false
 		}
-		return serviceaccount.MakeUsername(saNamespace, subject.Name) == user.GetName()
+		// use a more efficient comparison for RBAC checking
+		return serviceaccount.MatchesUsername(saNamespace, subject.Name, user.GetName())
 	default:
 		return false
 	}