klist: implement klist_add_{after|before}()

[mirror_ubuntu-bionic-kernel.git] / lib / klist.c

diff --git a/lib/klist.c b/lib/klist.c
index 120bd175aa7855044fdb5a440b6fc189b21344b3..ebba9488046ea7b8ed7ad01d66242c0efc703653 100644 (file)
--- a/lib/klist.c
+++ b/lib/klist.c
@@ -120,6 +120,39 @@ void klist_add_tail(struct klist_node * n, struct klist * k)
 EXPORT_SYMBOL_GPL(klist_add_tail);
 
 
+/**
+ * klist_add_after - Init a klist_node and add it after an existing node
+ * @n: node we're adding.
+ * @pos: node to put @n after
+ */
+void klist_add_after(struct klist_node *n, struct klist_node *pos)
+{
+       struct klist *k = pos->n_klist;
+
+       klist_node_init(k, n);
+       spin_lock(&k->k_lock);
+       list_add(&n->n_node, &pos->n_node);
+       spin_unlock(&k->k_lock);
+}
+EXPORT_SYMBOL_GPL(klist_add_after);
+
+/**
+ * klist_add_before - Init a klist_node and add it before an existing node
+ * @n: node we're adding.
+ * @pos: node to put @n after
+ */
+void klist_add_before(struct klist_node *n, struct klist_node *pos)
+{
+       struct klist *k = pos->n_klist;
+
+       klist_node_init(k, n);
+       spin_lock(&k->k_lock);
+       list_add_tail(&n->n_node, &pos->n_node);
+       spin_unlock(&k->k_lock);
+}
+EXPORT_SYMBOL_GPL(klist_add_before);
+
+
 static void klist_release(struct kref * kref)
 {
        struct klist_node * n = container_of(kref, struct klist_node, n_ref);