+/*
+ * Use the lowest bit of n_klist to mark deleted nodes and exclude
+ * dead ones from iteration.
+ */
+#define KNODE_DEAD 1LU
+#define KNODE_KLIST_MASK ~KNODE_DEAD
+
+static struct klist *knode_klist(struct klist_node *knode)
+{
+ return (struct klist *)
+ ((unsigned long)knode->n_klist & KNODE_KLIST_MASK);
+}
+
+static bool knode_dead(struct klist_node *knode)
+{
+ return (unsigned long)knode->n_klist & KNODE_DEAD;
+}
+
+static void knode_set_klist(struct klist_node *knode, struct klist *klist)
+{
+ knode->n_klist = klist;
+ /* no knode deserves to start its life dead */
+ WARN_ON(knode_dead(knode));
+}
+
+static void knode_kill(struct klist_node *knode)
+{
+ /* and no knode should die twice ever either, see we're very humane */
+ WARN_ON(knode_dead(knode));
+ *(unsigned long *)&knode->n_klist |= KNODE_DEAD;
+}