| 1 | #ifndef _LINUX_LIST_H |
| 2 | #define _LINUX_LIST_H |
| 3 | |
| 4 | /* |
| 5 | * These are non-NULL pointers that will result in page faults |
| 6 | * under normal circumstances, used to verify that nobody uses |
| 7 | * non-initialized list entries. |
| 8 | */ |
| 9 | #define LIST_POISON1 ((void *) 0x00100100) |
| 10 | #define LIST_POISON2 ((void *) 0x00200200) |
| 11 | |
| 12 | struct list_head { |
| 13 | struct list_head *next, *prev; |
| 14 | }; |
| 15 | |
| 16 | #define LIST_HEAD_INIT(name) { &(name), &(name) } |
| 17 | |
| 18 | #define LIST_HEAD(name) \ |
| 19 | struct list_head name = LIST_HEAD_INIT(name) |
| 20 | |
| 21 | static inline void INIT_LIST_HEAD(struct list_head *list) |
| 22 | { |
| 23 | list->next = list; |
| 24 | list->prev = list; |
| 25 | } |
| 26 | |
| 27 | /* |
| 28 | * Insert a new entry between two known consecutive entries. |
| 29 | * |
| 30 | * This is only for internal list manipulation where we know |
| 31 | * the prev/next entries already! |
| 32 | */ |
| 33 | static inline void __list_add(struct list_head *new, |
| 34 | struct list_head *prev, |
| 35 | struct list_head *next) |
| 36 | { |
| 37 | next->prev = new; |
| 38 | new->next = next; |
| 39 | new->prev = prev; |
| 40 | prev->next = new; |
| 41 | } |
| 42 | |
| 43 | /** |
| 44 | * list_add - add a new entry |
| 45 | * @new: new entry to be added |
| 46 | * @head: list head to add it after |
| 47 | * |
| 48 | * Insert a new entry after the specified head. |
| 49 | * This is good for implementing stacks. |
| 50 | */ |
| 51 | static inline void list_add(struct list_head *new, struct list_head *head) |
| 52 | { |
| 53 | __list_add(new, head, head->next); |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * list_add_tail - add a new entry |
| 58 | * @new: new entry to be added |
| 59 | * @head: list head to add it before |
| 60 | * |
| 61 | * Insert a new entry before the specified head. |
| 62 | * This is useful for implementing queues. |
| 63 | */ |
| 64 | static inline void list_add_tail(struct list_head *new, struct list_head *head) |
| 65 | { |
| 66 | __list_add(new, head->prev, head); |
| 67 | } |
| 68 | |
| 69 | /* |
| 70 | * Delete a list entry by making the prev/next entries |
| 71 | * point to each other. |
| 72 | * |
| 73 | * This is only for internal list manipulation where we know |
| 74 | * the prev/next entries already! |
| 75 | */ |
| 76 | static inline void __list_del(struct list_head * prev, struct list_head * next) |
| 77 | { |
| 78 | next->prev = prev; |
| 79 | prev->next = next; |
| 80 | } |
| 81 | |
| 82 | /** |
| 83 | * list_del - deletes entry from list. |
| 84 | * @entry: the element to delete from the list. |
| 85 | * Note: list_empty on entry does not return true after this, the entry is |
| 86 | * in an undefined state. |
| 87 | */ |
| 88 | static inline void list_del(struct list_head *entry) |
| 89 | { |
| 90 | __list_del(entry->prev, entry->next); |
| 91 | entry->next = LIST_POISON1; |
| 92 | entry->prev = LIST_POISON2; |
| 93 | } |
| 94 | |
| 95 | /** |
| 96 | * __list_for_each - iterate over a list |
| 97 | * @pos: the &struct list_head to use as a loop counter. |
| 98 | * @head: the head for your list. |
| 99 | * |
| 100 | * This variant differs from list_for_each() in that it's the |
| 101 | * simplest possible list iteration code, no prefetching is done. |
| 102 | * Use this for code that knows the list to be very short (empty |
| 103 | * or 1 entry) most of the time. |
| 104 | */ |
| 105 | #define __list_for_each(pos, head) \ |
| 106 | for (pos = (head)->next; pos != (head); pos = pos->next) |
| 107 | |
| 108 | /** |
| 109 | * list_for_each_safe - iterate over a list safe against removal of list entry |
| 110 | * @pos: the &struct list_head to use as a loop counter. |
| 111 | * @n: another &struct list_head to use as temporary storage |
| 112 | * @head: the head for your list. |
| 113 | */ |
| 114 | #define list_for_each_safe(pos, n, head) \ |
| 115 | for (pos = (head)->next, n = pos->next; pos != (head); \ |
| 116 | pos = n, n = pos->next) |
| 117 | |
| 118 | /** |
| 119 | * list_entry - get the struct for this entry |
| 120 | * @ptr: the &struct list_head pointer. |
| 121 | * @type: the type of the struct this is embedded in. |
| 122 | * @member: the name of the list_struct within the struct. |
| 123 | */ |
| 124 | #define list_entry(ptr, type, member) \ |
| 125 | container_of(ptr, type, member) |
| 126 | |
| 127 | static inline int list_len(struct list_head *head_p) |
| 128 | { |
| 129 | struct list_head *p; |
| 130 | int n = 0; |
| 131 | |
| 132 | __list_for_each(p, head_p) { |
| 133 | n++; |
| 134 | } |
| 135 | |
| 136 | return n; |
| 137 | } |
| 138 | |
| 139 | /** |
| 140 | * list_empty - tests whether a list is empty |
| 141 | * @head: the list to test. |
| 142 | */ |
| 143 | static inline int list_empty(const struct list_head *head) |
| 144 | { |
| 145 | return head->next == head; |
| 146 | } |
| 147 | |
| 148 | #endif |