From 63aaee1b76194fa8392fc28d9a2d3a4c9f150a90 Mon Sep 17 00:00:00 2001
From: Richard Fuchs <rfuchs@sipwise.com>
Date: Tue, 11 Nov 2025 10:04:38 -0400
Subject: [PATCH] MT#55283 add intrusive queue container

Change-Id: Ib706a257b90428f8a37503e41c040ffc93d36839
---
 lib/iqueue.h | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 lib/iqueue.h

diff --git a/lib/iqueue.h b/lib/iqueue.h
new file mode 100644
index 000000000..ca1beee2e
--- /dev/null
+++ b/lib/iqueue.h
@@ -0,0 +1,87 @@
+#ifndef __IQUEUE_H__
+#define __IQUEUE_H__
+
+
+#include <stddef.h>
+
+
+#define IQUEUE_LINK \
+	struct { \
+		void *prev; \
+		void *next; \
+	}
+
+
+#define IQUEUE_TYPE(ele_type, link_name) \
+	struct { \
+		union { \
+			struct { \
+				ele_type *head; \
+				ele_type *tail; \
+				unsigned int length; \
+			}; \
+			struct { \
+				char dummy[offsetof(ele_type, link_name)]; \
+				struct { \
+					ele_type *prev; \
+					ele_type *next; \
+				} link; \
+			} *offset; \
+		}; \
+	}
+
+
+#define IQUEUE(ele_type, link_name, queue_name) \
+	IQUEUE_TYPE(ele_type, link_name) queue_name
+
+
+#define i_queue_init(list) do { \
+	(list)->head = NULL; \
+	(list)->tail = NULL; \
+	(list)->length = 0; \
+} while (0)
+
+
+#define IQUEUE_INIT { 0 }
+
+
+#define i_queue_peek_head(list) ({ \
+	__auto_type __ret = (list)->head; \
+	__ret; \
+})
+
+
+#define i_queue_pop_head(list) ({ \
+	__auto_type __ret = (list)->head; \
+	if (__ret) { \
+		__auto_type __link = (__typeof((list)->offset)) __ret; \
+		(list)->head = __link->link.next; \
+		__link->link.next = NULL; \
+		(list)->length--; \
+		if (!(list)->head) \
+			(list)->tail = NULL; \
+	} \
+	__ret; \
+})
+
+
+#define i_queue_push_tail(list, ele) do { \
+	if ((list)->tail) { \
+		__auto_type __link = (__typeof((list)->offset)) (list)->tail; \
+		__link->link.next = ele; \
+	} \
+	__auto_type __link = (__typeof((list)->offset)) ele; \
+	__link->link.prev = (list)->tail; \
+	(list)->tail = ele; \
+	if (!(list)->head) \
+		(list)->head = ele; \
+	(list)->length++; \
+} while (0)
+
+
+#define IQUEUE_FOREACH(list, var) \
+	for (__typeof__ ( ({ __typeof__ (*(list)->head) __t; &__t; }) ) var = (list)->head; \
+			var; var = ((__typeof((list)->offset)) var)->link.next)
+
+
+#endif