1 #ifndef _LIST_H 2 #define _LIST_H 3 4 /* 5 * This code was taken from the Linux 2.4.0 kernel. [jaroslav] 6 */ 7 8 /* 9 * Simple doubly linked list implementation. 10 * 11 * Some of the internal functions ("__xxx") are useful when 12 * manipulating whole lists rather than single entries, as 13 * sometimes we already know the next/prev entries and we can 14 * generate better code by using them directly rather than 15 * using the generic single-entry routines. 16 */ 17 18 #ifndef LIST_HEAD_IS_DEFINED 19 struct list_head { 20 struct list_head *next, *prev; 21 }; 22 #endif 23 24 #define LIST_HEAD_INIT(name) { &(name), &(name) } 25 26 #define LIST_HEAD(name) \ 27 struct list_head name = LIST_HEAD_INIT(name) 28 29 #define INIT_LIST_HEAD(ptr) do { \ 30 (ptr)->next = (ptr); (ptr)->prev = (ptr); \ 31 } while (0) 32 33 /* 34 * Insert a new entry between two known consecutive entries. 35 * 36 * This is only for internal list manipulation where we know 37 * the prev/next entries already! 38 */ 39 static __inline__ void __list_add(struct list_head * _new, 40 struct list_head * prev, 41 struct list_head * next) 42 { 43 next->prev = _new; 44 _new->next = next; 45 _new->prev = prev; 46 prev->next = _new; 47 } 48 49 /** 50 * list_add - add a new entry 51 * @new: new entry to be added 52 * @head: list head to add it after 53 * 54 * Insert a new entry after the specified head. 55 * This is good for implementing stacks. 56 */ 57 static __inline__ void list_add(struct list_head *_new, struct list_head *head) 58 { 59 __list_add(_new, head, head->next); 60 } 61 62 /** 63 * list_add_tail - add a new entry 64 * @new: new entry to be added 65 * @head: list head to add it before 66 * 67 * Insert a new entry before the specified head. 68 * This is useful for implementing queues. 69 */ 70 static __inline__ void list_add_tail(struct list_head *_new, struct list_head *head) 71 { 72 __list_add(_new, head->prev, head); 73 } 74 75 /* 76 * Delete a list entry by making the prev/next entries 77 * point to each other. 78 * 79 * This is only for internal list manipulation where we know 80 * the prev/next entries already! 81 */ 82 static __inline__ void __list_del(struct list_head * prev, 83 struct list_head * next) 84 { 85 next->prev = prev; 86 prev->next = next; 87 } 88 89 /** 90 * list_del - deletes entry from list. 91 * @entry: the element to delete from the list. 92 * Note: list_empty on entry does not return true after this, the entry is in an undefined state. 93 */ 94 static __inline__ void list_del(struct list_head *entry) 95 { 96 __list_del(entry->prev, entry->next); 97 } 98 99 /** 100 * list_del_init - deletes entry from list and reinitialize it. 101 * @entry: the element to delete from the list.n 102 */ 103 static __inline__ void list_del_init(struct list_head *entry) 104 { 105 __list_del(entry->prev, entry->next); 106 INIT_LIST_HEAD(entry); 107 } 108 109 /** 110 * list_empty - tests whether a list is empty 111 * @head: the list to test. 112 */ 113 static __inline__ int list_empty(struct list_head *head) 114 { 115 return head->next == head; 116 } 117 118 /** 119 * list_splice - join two lists 120 * @list: the new list to add. 121 * @head: the place to add it in the first list. 122 */ 123 static __inline__ void list_splice(struct list_head *list, struct list_head *head) 124 { 125 struct list_head *first = list->next; 126 127 if (first != list) { 128 struct list_head *last = list->prev; 129 struct list_head *at = head->next; 130 131 first->prev = head; 132 head->next = first; 133 134 last->next = at; 135 at->prev = last; 136 } 137 } 138 139 /** 140 * list_for_each - iterate over a list 141 * @pos: the &struct list_head to use as a loop counter. 142 * @head: the head for your list. 143 */ 144 #define list_for_each(pos, head) \ 145 for (pos = (head)->next ; pos != (head); pos = pos->next) 146 147 /** 148 * list_for_each_safe - iterate over a list safely (actual pointer can be invalidated) 149 * @pos: the &struct list_head to use as a loop counter. 150 * @next: the &struct list_head to use to save next. 151 * @head: the head for your list. 152 */ 153 #define list_for_each_safe(pos, npos, head) \ 154 for (pos = (head)->next, npos = pos->next ; pos != (head); pos = npos, npos = pos->next) 155 156 /** 157 * list_entry - get the struct for this entry 158 * @ptr: the &struct list_head pointer. 159 * @type: the type of the struct this is embedded in. 160 * @member: the name of the list_struct within the struct. 161 */ 162 #define list_entry(ptr, type, member) \ 163 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) 164 165 166 #endif /* _LIST_H */ 167
