2 * YAFFS: Yet another Flash File System . A NAND-flash specific file system.
4 * Copyright (C) 2002-2010 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
7 * Created by Charles Manning <charles@aleph1.co.uk>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License version 2.1 as
11 * published by the Free Software Foundation.
13 * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
17 * This file is just holds extra declarations of macros that would normally
18 * be providesd in the Linux kernel. These macros have been written from
19 * scratch but are functionally equivalent to the Linux ones.
23 #ifndef __YAFFS_LIST_H__
24 #define __YAFFS_LIST_H__
30 * This is a simple doubly linked list implementation that matches the
31 * way the Linux kernel doubly linked list implementation works.
35 struct list_head *next; /* next in chain */
36 struct list_head *prev; /* previous in chain */
40 /* Initialise a static list */
41 #define LIST_HEAD(name) \
42 struct list_head name = { &(name), &(name)}
46 /* Initialise a list head to an empty list */
47 #define INIT_LIST_HEAD(p) \
54 /* Add an element to a list */
55 static inline void list_add(struct list_head *new_entry,
56 struct list_head *list)
58 struct list_head *list_next = list->next;
60 list->next = new_entry;
61 new_entry->prev = list;
62 new_entry->next = list_next;
63 list_next->prev = new_entry;
67 static inline void list_add_tail(struct list_head *new_entry,
68 struct list_head *list)
70 struct list_head *list_prev = list->prev;
72 list->prev = new_entry;
73 new_entry->next = list;
74 new_entry->prev = list_prev;
75 list_prev->next = new_entry;
80 /* Take an element out of its current list, with or without
81 * reinitialising the links.of the entry*/
82 static inline void list_del(struct list_head *entry)
84 struct list_head *list_next = entry->next;
85 struct list_head *list_prev = entry->prev;
87 list_next->prev = list_prev;
88 list_prev->next = list_next;
92 static inline void list_del_init(struct list_head *entry)
95 entry->next = entry->prev = entry;
99 /* Test if the list is empty */
100 static inline int list_empty(struct list_head *entry)
102 return (entry->next == entry);
106 /* list_entry takes a pointer to a list entry and offsets it to that
107 * we can find a pointer to the object it is embedded in.
111 #define list_entry(entry, type, member) \
112 ((type *)((char *)(entry)-(unsigned long)(&((type *)NULL)->member)))
115 /* list_for_each and list_for_each_safe iterate over lists.
116 * list_for_each_safe uses temporary storage to make the list delete safe
119 #define list_for_each(itervar, list) \
120 for (itervar = (list)->next; itervar != (list); itervar = itervar->next)
122 #define list_for_each_safe(itervar, save_var, list) \
123 for (itervar = (list)->next, save_var = (list)->next->next; \
124 itervar != (list); itervar = save_var, save_var = save_var->next)