mtd-utils: Extract list implementation to common lib and add list_sort support

Current list implementation code is put under jffs utils, extract it into
common lib, and add more list operations(eg. list_move, list_splice, etc.).
Besides, add list sorting support in new source file lib/list_sort.c.

This is a preparation for replacing implementation of UBIFS utils with
linux kernel libs.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 263 insertions, 0 deletions

diff --git a/include/list.h b/include/list.h
new file mode 100644
index 0000000..d26c9d1
--- /dev/null
+++ b/include/list.h
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2006 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#ifndef __LIST_H__
+#define __LIST_H__
+
+#include <stddef.h>
+
+/*
+ * This undef is here because BSD 4.4 added some LIST_ macros into system
+ * header file sys/queue.h. This header is included in many other system
+ * headers and thus causes "macro redefined" warnings.
+ *
+ * As OS X is kind of a derivate of BSD, this affects OS X too.
+ *
+ * To use our own LIST_ macros (copied from kernel code), we have to
+ * at first undefine the conflicting system macros.
+ *
+ */
+#undef LIST_HEAD
+#undef LIST_HEAD_INIT
+
+/*
+ * Simple, generic doubly-linked list implementation.
+ */
+
+struct list_head {
+	struct list_head *next;
+	struct list_head *prev;
+};
+
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
+
+#define LIST_HEAD(name) \
+		struct list_head name = LIST_HEAD_INIT(name)
+
+#define INIT_LIST_HEAD(list) list_head_init(list)
+static inline void list_head_init(struct list_head *list)
+{
+	list->next = list->prev = list;
+}
+
+static inline void list_head_destroy(struct list_head *list)
+{
+	list->next = list->prev = NULL;
+}
+
+static inline void __list_add(struct list_head *add,
+			      struct list_head *prev, struct list_head *next)
+{
+	next->prev = add;
+	add->next = next;
+	add->prev = prev;
+	prev->next = add;
+}
+
+static inline void list_add(struct list_head *add, struct list_head *head)
+{
+	__list_add(add, head, head->next);
+}
+
+static inline void list_add_tail(struct list_head *add, struct list_head *head)
+{
+	__list_add(add, 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_init(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
+	list_head_init(entry);
+}
+
+static inline void list_del(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
+}
+
+static inline void list_move(struct list_head *list, struct list_head *head)
+{
+	__list_del(list->prev, list->next);
+	list_add(list, head);
+}
+
+static inline void list_move_tail(struct list_head *list, struct list_head *head)
+{
+	__list_del(list->prev, list->next);
+	list_add_tail(list, head);
+}
+
+/**
+ * list_is_last - tests whether @list is the last entry in list @head
+ * @list: the entry to test
+ * @head: the head of the list
+ */
+static inline int list_is_last(const struct list_head *list, const struct list_head *head)
+{
+	return list->next == head;
+}
+
+static inline int list_empty(const struct list_head *head)
+{
+	return head->next == head;
+}
+
+static inline void __list_splice(struct list_head *list,
+				 struct list_head *prev,
+				 struct list_head *next)
+{
+	struct list_head *first = list->next;
+	struct list_head *last = list->prev;
+
+	first->prev = prev;
+	prev->next = first;
+
+	last->next = next;
+	next->prev = last;
+}
+
+static inline void list_splice(struct list_head *list, struct list_head *head)
+{
+	if (!list_empty(list))
+		__list_splice(list, head, head->next);
+}
+
+static inline void list_splice_tail(struct list_head *list,
+				    struct list_head *head)
+{
+	if (!list_empty(list))
+		__list_splice(list, head->prev, head);
+}
+
+static inline void list_splice_init(struct list_head *list,
+				    struct list_head *head)
+{
+	if (!list_empty(list)) {
+		__list_splice(list, head, head->next);
+		list_head_init(list);
+	}
+}
+
+#define list_entry(ptr, type, member) ({			\
+	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
+	(type *)( (char *)__mptr - offsetof(type,member) );})
+
+#define list_for_each(pos, head) \
+	for (pos = (head)->next; pos != (head); pos = pos->next)
+
+#define list_for_each_safe(pos, n, head) \
+	for (pos = (head)->next, n = pos->next; pos != (head); \
+		pos = n, n = pos->next)
+
+#define list_for_each_entry(pos, head, member)				\
+	for (pos = list_entry((head)->next, typeof(*pos), member);	\
+	     &pos->member != (head); 	\
+	     pos = list_entry(pos->member.next, typeof(*pos), member))
+
+#define list_for_each_entry_safe(pos, n, head, member)			\
+	for (pos = list_entry((head)->next, typeof(*pos), member),	\
+		n = list_entry(pos->member.next, typeof(*pos), member);	\
+	     &pos->member != (head); 					\
+	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
+
+#define list_first_entry(ptr, type, member) \
+	list_entry((ptr)->next, type, member)
+
+#define container_of(ptr, type, member) ({			\
+	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
+	(type *)( (char *)__mptr - offsetof(type,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))
+
+typedef int __attribute__((nonnull(2,3))) (*list_cmp_func_t)(void *,
+			const struct list_head *, const struct list_head *);
+__attribute__((nonnull(2,3)))
+void list_sort(void *priv, struct list_head *head, list_cmp_func_t cmp);
+
+/**
+ * list_splice_tail_init - join two lists and reinitialise the emptied list
+ * @list: the new list to add.
+ * @head: the place to add it in the first list.
+ *
+ * Each of the lists is a queue.
+ * The list at @list is reinitialised
+ */
+static inline void list_splice_tail_init(struct list_head *list,
+					 struct list_head *head)
+{
+	if (!list_empty(list)) {
+		__list_splice(list, head->prev, head);
+		INIT_LIST_HEAD(list);
+	}
+}
+
+/**
+ * list_replace - replace old entry by new one
+ * @old : the element to be replaced
+ * @new : the new element to insert
+ *
+ * If @old was empty, it will be overwritten.
+ */
+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;
+}
+
+/**
+ * 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_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_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_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);		\
+	     &pos->member != (head); 					\
+	     pos = list_prev_entry(pos, member))
+
+#endif	/* __LIST_H__ */