1 files changed, 72 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h
new file mode 100644
index 0000000000..9939085d0e
--- /dev/null
+++ b/include/linux/idr.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * include/linux/idr.h
+ *
+ * 2002-10-18  written by Jim Houston jim.houston@ccur.com
+ *	Copyright (C) 2002 by Concurrent Computer Corporation
+ *
+ * Small id to pointer translation service avoiding fixed sized
+ * tables.
+ */
+
+#ifndef __IDR_H__
+#define __IDR_H__
+
+#include <errno.h>
+#include <linux/list.h>
+
+struct idr {
+	int			id;
+	void			*ptr;
+	struct list_head	list;
+};
+
+#define DEFINE_IDR(name)	\
+	struct idr name = { .list = LIST_HEAD_INIT((name).list) }
+
+/**
+ * idr_for_each_entry() - Iterate over an IDR's elements of a given type.
+ * @_idr: IDR handle.
+ * @_entry: The type * to use as cursor
+ * @_id: Entry ID.
+ *
+ * @_entry and @_id do not need to be initialized before the loop, and
+ * after normal termination @_entry is left with the value NULL.  This
+ * is convenient for a "not found" value.
+ */
+#define idr_for_each_entry(_idr, _entry, _id)				\
+	for (struct idr *iter =						\
+	     list_first_entry_or_null(&(_idr)->list, struct idr, list);	\
+	     (iter && iter != (_idr)) || (_entry = NULL);	\
+	     iter = list_next_entry(iter, list))			\
+	if ((_entry = iter->ptr, _id = iter->id, true))
+
+struct idr *__idr_find(struct idr *head, int lookup_id);
+
+int idr_for_each(const struct idr *idr,
+		 int (*fn)(int id, void *p, void *data), void *data);
+
+static inline int idr_is_empty(const struct idr *idr)
+{
+	return list_empty(&idr->list);
+}
+
+static inline void *idr_find(struct idr *head, int id)
+{
+	struct idr *idr = __idr_find(head, id);
+
+	return idr ? idr->ptr : NULL;
+}
+
+int idr_alloc_one(struct idr *head, void *ptr, int start);
+
+static inline void idr_init(struct idr *idr)
+{
+	INIT_LIST_HEAD(&idr->list);
+}
+
+void idr_destroy(struct idr *idr);
+
+void idr_remove(struct idr *idr, int id);
+
+#endif /* __IDR_H__ */