v4.19.13 snapshot.
diff --git a/include/linux/klist.h b/include/linux/klist.h
new file mode 100644
index 0000000..953f283
--- /dev/null
+++ b/include/linux/klist.h
@@ -0,0 +1,69 @@
+/*
+ * klist.h - Some generic list helpers, extending struct list_head a bit.
+ *
+ * Implementations are found in lib/klist.c
+ *
+ *
+ * Copyright (C) 2005 Patrick Mochel
+ *
+ * This file is rleased under the GPL v2.
+ */
+
+#ifndef _LINUX_KLIST_H
+#define _LINUX_KLIST_H
+
+#include <linux/spinlock.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+
+struct klist_node;
+struct klist {
+ spinlock_t k_lock;
+ struct list_head k_list;
+ void (*get)(struct klist_node *);
+ void (*put)(struct klist_node *);
+} __attribute__ ((aligned (sizeof(void *))));
+
+#define KLIST_INIT(_name, _get, _put) \
+ { .k_lock = __SPIN_LOCK_UNLOCKED(_name.k_lock), \
+ .k_list = LIST_HEAD_INIT(_name.k_list), \
+ .get = _get, \
+ .put = _put, }
+
+#define DEFINE_KLIST(_name, _get, _put) \
+ struct klist _name = KLIST_INIT(_name, _get, _put)
+
+extern void klist_init(struct klist *k, void (*get)(struct klist_node *),
+ void (*put)(struct klist_node *));
+
+struct klist_node {
+ void *n_klist; /* never access directly */
+ struct list_head n_node;
+ struct kref n_ref;
+};
+
+extern void klist_add_tail(struct klist_node *n, struct klist *k);
+extern void klist_add_head(struct klist_node *n, struct klist *k);
+extern void klist_add_behind(struct klist_node *n, struct klist_node *pos);
+extern void klist_add_before(struct klist_node *n, struct klist_node *pos);
+
+extern void klist_del(struct klist_node *n);
+extern void klist_remove(struct klist_node *n);
+
+extern int klist_node_attached(struct klist_node *n);
+
+
+struct klist_iter {
+ struct klist *i_klist;
+ struct klist_node *i_cur;
+};
+
+
+extern void klist_iter_init(struct klist *k, struct klist_iter *i);
+extern void klist_iter_init_node(struct klist *k, struct klist_iter *i,
+ struct klist_node *n);
+extern void klist_iter_exit(struct klist_iter *i);
+extern struct klist_node *klist_prev(struct klist_iter *i);
+extern struct klist_node *klist_next(struct klist_iter *i);
+
+#endif