2 * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
4 * Copyright (C) 2002-2018 Aleph One Ltd.
6 * Created by Charles Manning <charles@aleph1.co.uk>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU Lesser General Public License version 2.1 as
10 * published by the Free Software Foundation.
12 * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
16 * This file is just holds extra declarations of macros that would normally
17 * be providesd in the Linux kernel. These macros have been written from
18 * scratch but are functionally equivalent to the Linux ones.
22 #ifndef __YAFFS_LIST_H__
23 #define __YAFFS_LIST_H__
27 * This is a simple doubly linked list implementation that matches the
28 * way the Linux kernel doubly linked list implementation works.
32 struct list_head *next; /* next in chain */
33 struct list_head *prev; /* previous in chain */
37 /* Initialise a static list */
42 #define LIST_HEAD(name) \
43 struct list_head name = { &(name), &(name)}
47 /* Initialise a list head to an empty list */
48 #define INIT_LIST_HEAD(p) \
55 /* Add an element to a list */
56 static inline void list_add(struct list_head *new_entry,
57 struct list_head *list)
59 struct list_head *list_next = list->next;
61 list->next = new_entry;
62 new_entry->prev = list;
63 new_entry->next = list_next;
64 list_next->prev = new_entry;
68 static inline void list_add_tail(struct list_head *new_entry,
69 struct list_head *list)
71 struct list_head *list_prev = list->prev;
73 list->prev = new_entry;
74 new_entry->next = list;
75 new_entry->prev = list_prev;
76 list_prev->next = new_entry;
81 /* Take an element out of its current list, with or without
82 * reinitialising the links.of the entry*/
83 static inline void list_del(struct list_head *entry)
85 struct list_head *list_next = entry->next;
86 struct list_head *list_prev = entry->prev;
88 list_next->prev = list_prev;
89 list_prev->next = list_next;
93 static inline void list_del_init(struct list_head *entry)
96 entry->next = entry->prev = entry;
100 /* Test if the list is empty */
101 static inline int list_empty(struct list_head *entry)
103 return (entry->next == entry);
107 /* list_entry takes a pointer to a list entry and offsets it to that
108 * we can find a pointer to the object it is embedded in.
112 #define list_entry(entry, type, member) \
113 ((type *)((char *)(entry)-(unsigned long)(&((type *)NULL)->member)))
116 /* list_for_each and list_for_each_safe iterate over lists.
117 * list_for_each_safe uses temporary storage to make the list delete safe
120 #define list_for_each(itervar, list) \
121 for (itervar = (list)->next; itervar != (list); itervar = itervar->next)
123 #define list_for_each_safe(itervar, save_var, list) \
124 for (itervar = (list)->next, save_var = (list)->next->next; \
126 itervar = save_var, save_var = save_var->next)