Implement intrusive linked list

2 files changed, 240 insertions, 0 deletions

diff --git a/lab02/container_of.h b/lab02/container_of.h
new file mode 100644
index 0000000..6383572
--- /dev/null
+++ b/lab02/container_of.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CONTAINER_OF_H
+#define _CONTAINER_OF_H
+
+#include <stddef.h>
+
+#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
+
+#undef offsetof
+#define offsetof(TYPE, MEMBER)	__builtin_offsetof(TYPE, MEMBER)
+
+#define typeof_member(T, m)   typeof(((T*)0)->m)
+
+
+#define container_of(ptr, type, member) ({                         \
+    _Static_assert(__same_type(*(ptr), typeof_member(type, member)) || \
+                   __same_type(*(ptr), void),                      \
+                   "pointer type mismatch in container_of()");     \
+    (type *)((void *)(ptr) - offsetof(type, member)); })
+
+
+#define container_of_const(ptr, type, member)				\
+	_Generic(ptr,							\
+		const typeof(*(ptr)) *: ((const type *)container_of(ptr, type, member)),\
+		default: ((type *)container_of(ptr, type, member))	\
+	)
+
+#endif /* _CONTAINER_OF_H */
diff --git a/lab02/list.h b/lab02/list.h
new file mode 100644
index 0000000..f04df43
--- /dev/null
+++ b/lab02/list.h
@@ -0,0 +1,212 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LIST_H
+#define LIST_H
+
+#include <stddef.h>
+#include <stdbool.h>
+#include <assert.h>
+
+#include "container_of.h"
+
+struct list_head {
+  struct list_head *next;
+  struct list_head *prev;
+};
+
+#define LIST_POISON1  ((void *) 0x100)
+#define LIST_POISON2  ((void *) 0x122)
+
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
+
+#define LIST_HEAD(name) \
+    struct list_head name = LIST_HEAD_INIT(name)
+
+static inline void INIT_LIST_HEAD(struct list_head *list)
+{
+    list->next = list;
+    list->prev = list;
+}
+
+static inline void __list_add(struct list_head *node,
+                              struct list_head *prev,
+                              struct list_head *next)
+{
+    next->prev = node;
+    node->next = next;
+    node->prev = prev;
+    prev->next = node;
+}
+
+static inline void list_add(struct list_head *node,
+                            struct list_head *head)
+{
+    __list_add(node, head, head->next);
+}
+
+static inline void list_add_tail(struct list_head *node,
+                                 struct list_head *head)
+{
+    __list_add(node, head->prev, head);
+}
+
+static inline void __list_del(struct list_head *prev,
+                              struct list_head *next)
+{
+    next->prev = prev;
+    prev->next = next;
+}
+
+static inline void __list_del_entry(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
+}
+
+static inline void list_del(struct list_head *entry)
+{
+	__list_del_entry(entry);
+	entry->next = LIST_POISON1;
+	entry->prev = LIST_POISON2;
+}
+
+
+static inline void list_replace(struct list_head *old,
+				struct list_head *new)
+{
+	new->next = old->next;
+	new->next->prev = new;
+	new->prev = old->prev;
+	new->prev->next = new;
+}
+
+static inline void list_replace_init(struct list_head *old,
+				     struct list_head *new)
+{
+	list_replace(old, new);
+	INIT_LIST_HEAD(old);
+}
+
+static inline void list_move(struct list_head *list, struct list_head *head)
+{
+	__list_del_entry(list);
+	list_add(list, head);
+}
+
+static inline void list_move_tail(struct list_head *list,
+				  struct list_head *head)
+{
+	__list_del_entry(list);
+	list_add_tail(list, head);
+}
+
+static inline int list_is_first(const struct list_head *list, const struct list_head *head)
+{
+	return list->prev == head;
+}
+
+static inline int list_is_last(const struct list_head *list, const struct list_head *head)
+{
+	return list->next == head;
+}
+
+static inline int list_is_head(const struct list_head *list, const struct list_head *head)
+{
+	return list == head;
+}
+
+static inline int list_empty(const struct list_head *head)
+{
+	return head->next == head;
+}
+
+/**
+ * list_entry - get the struct for this entry
+ * @ptr:	the &struct list_head pointer.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_entry(ptr, type, member) \
+	container_of(ptr, type, member)
+
+/**
+ * list_first_entry - get the first element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member) \
+	list_entry((ptr)->next, type, member)
+
+/**
+ * list_last_entry - get the last element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_last_entry(ptr, type, member) \
+	list_entry((ptr)->prev, type, member)
+
+/**
+ * list_next_entry - get the next element in list
+ * @pos:	the type * to cursor
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_next_entry(pos, member) \
+	list_entry((pos)->member.next, typeof(*(pos)), member)
+
+/**
+ * list_prev_entry - get the prev element in list
+ * @pos:	the type * to cursor
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_prev_entry(pos, member) \
+	list_entry((pos)->member.prev, typeof(*(pos)), member)
+
+/**
+ * list_entry_is_head - test if the entry points to the head of the list
+ * @pos:	the type * to cursor
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_entry_is_head(pos, head, member)				\
+	(&pos->member == (head))
+
+/**
+ * list_for_each_entry - iterate over list of given type
+ * @pos:	the type * to use as a loop cursor.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry(pos, head, member)				\
+	for (pos = list_first_entry(head, typeof(*pos), member);	\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_reverse - iterate backwards over list of given type.
+ * @pos:	the type * to use as a loop cursor.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry_reverse(pos, head, member)			\
+	for (pos = list_last_entry(head, typeof(*pos), member);		\
+	     !list_entry_is_head(pos, head, member); 			\
+	     pos = list_prev_entry(pos, member))
+
+/**
+ * list_for_each_entry_safe - iterate over list of given type. Safe against removal of list entry
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry_safe(pos, n, head, member)			\
+	for (pos = list_first_entry(head, typeof(*pos), member),	\
+		n = list_next_entry(pos, member);			\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = n, n = list_next_entry(n, member))
+
+#endif /* LIST_H */