1 files changed, 79 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h
new file mode 100644
index 0000000000..8a0f452d76
--- /dev/null
+++ b/include/linux/idr.h
@@ -0,0 +1,79 @@
+/* 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) }
+
+#define __idr_for_each_entry(head, idr) \
+	list_for_each_entry((idr), &(head)->list, list)
+
+static inline struct idr *__idr_find(struct idr *head, int id)
+{
+	struct idr *idr;
+
+	__idr_for_each_entry(head, idr) {
+		if (idr->id == id)
+			return idr;
+	}
+
+	return NULL;
+}
+
+static inline void *idr_find(struct idr *head, int id)
+{
+	struct idr *idr = __idr_find(head, id);
+
+	return idr ? idr->ptr : NULL;
+}
+
+static inline int idr_alloc_one(struct idr *head, void *ptr, int start)
+{
+	struct idr *idr;
+
+	if (__idr_find(head, start))
+		return -EBUSY;
+
+	idr = malloc(sizeof(*idr));
+
+	idr->id = start;
+	idr->ptr = ptr;
+
+	list_add(&idr->list, &head->list);
+
+	return start;
+}
+
+static inline void idr_init(struct idr *idr)
+{
+	INIT_LIST_HEAD(&idr->list);
+}
+
+static inline void idr_remove(struct idr *head, int id)
+{
+	struct idr *idr = __idr_find(head, id);
+
+	list_del(&idr->list);
+	free(idr);
+}
+
+#endif /* __IDR_H__ */