[821] | 1 | #if !defined(_BLKID_LIST_H) && !defined(LIST_HEAD)
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| 2 | #define _BLKID_LIST_H
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| 3 |
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| 4 | #ifdef __cplusplus
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| 5 | extern "C" {
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| 6 | #endif
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| 7 |
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| 8 | #ifdef __GNUC__
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| 9 | #define _INLINE_ static __inline__
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| 10 | #else /* For Watcom C */
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| 11 | #define _INLINE_ static inline
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| 12 | #endif
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| 13 |
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| 14 | /*
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| 15 | * Simple doubly linked list implementation.
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| 16 | *
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| 17 | * Some of the internal functions ("__xxx") are useful when
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| 18 | * manipulating whole lists rather than single entries, as
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| 19 | * sometimes we already know the next/prev entries and we can
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| 20 | * generate better code by using them directly rather than
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| 21 | * using the generic single-entry routines.
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| 22 | */
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| 23 |
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| 24 | struct list_head {
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| 25 | struct list_head *next, *prev;
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| 26 | };
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| 27 |
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| 28 | #define LIST_HEAD_INIT(name) { &(name), &(name) }
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| 29 |
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| 30 | #define LIST_HEAD(name) \
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| 31 | struct list_head name = LIST_HEAD_INIT(name)
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| 32 |
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| 33 | #define INIT_LIST_HEAD(ptr) do { \
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| 34 | (ptr)->next = (ptr); (ptr)->prev = (ptr); \
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| 35 | } while (0)
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| 36 |
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| 37 | /*
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| 38 | * Insert a new entry between two known consecutive entries.
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| 39 | *
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| 40 | * This is only for internal list manipulation where we know
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| 41 | * the prev/next entries already!
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| 42 | */
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| 43 | _INLINE_ void __list_add(struct list_head * add,
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| 44 | struct list_head * prev,
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| 45 | struct list_head * next)
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| 46 | {
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| 47 | next->prev = add;
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| 48 | add->next = next;
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| 49 | add->prev = prev;
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| 50 | prev->next = add;
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| 51 | }
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| 52 |
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| 53 | /**
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| 54 | * list_add - add a new entry
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| 55 | * @add: new entry to be added
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| 56 | * @head: list head to add it after
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| 57 | *
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| 58 | * Insert a new entry after the specified head.
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| 59 | * This is good for implementing stacks.
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| 60 | */
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| 61 | _INLINE_ void list_add(struct list_head *add, struct list_head *head)
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| 62 | {
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| 63 | __list_add(add, head, head->next);
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| 64 | }
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| 65 |
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| 66 | /**
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| 67 | * list_add_tail - add a new entry
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| 68 | * @add: new entry to be added
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| 69 | * @head: list head to add it before
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| 70 | *
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| 71 | * Insert a new entry before the specified head.
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| 72 | * This is useful for implementing queues.
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| 73 | */
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| 74 | _INLINE_ void list_add_tail(struct list_head *add, struct list_head *head)
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| 75 | {
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| 76 | __list_add(add, head->prev, head);
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| 77 | }
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| 78 |
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| 79 | /*
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| 80 | * Delete a list entry by making the prev/next entries
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| 81 | * point to each other.
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| 82 | *
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| 83 | * This is only for internal list manipulation where we know
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| 84 | * the prev/next entries already!
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| 85 | */
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| 86 | _INLINE_ void __list_del(struct list_head * prev,
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| 87 | struct list_head * next)
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| 88 | {
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| 89 | next->prev = prev;
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| 90 | prev->next = next;
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| 91 | }
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| 92 |
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| 93 | /**
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| 94 | * list_del - deletes entry from list.
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| 95 | * @entry: the element to delete from the list.
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| 96 | *
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| 97 | * list_empty() on @entry does not return true after this, @entry is
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| 98 | * in an undefined state.
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| 99 | */
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| 100 | _INLINE_ void list_del(struct list_head *entry)
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| 101 | {
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| 102 | __list_del(entry->prev, entry->next);
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| 103 | }
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| 104 |
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| 105 | /**
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| 106 | * list_del_init - deletes entry from list and reinitialize it.
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| 107 | * @entry: the element to delete from the list.
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| 108 | */
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| 109 | _INLINE_ void list_del_init(struct list_head *entry)
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| 110 | {
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| 111 | __list_del(entry->prev, entry->next);
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| 112 | INIT_LIST_HEAD(entry);
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| 113 | }
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| 114 |
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| 115 | /**
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| 116 | * list_empty - tests whether a list is empty
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| 117 | * @head: the list to test.
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| 118 | */
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| 119 | _INLINE_ int list_empty(struct list_head *head)
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| 120 | {
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| 121 | return head->next == head;
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| 122 | }
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| 123 |
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| 124 | /**
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| 125 | * list_splice - join two lists
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| 126 | * @list: the new list to add.
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| 127 | * @head: the place to add it in the first list.
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| 128 | */
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| 129 | _INLINE_ void list_splice(struct list_head *list, struct list_head *head)
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| 130 | {
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| 131 | struct list_head *first = list->next;
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| 132 |
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| 133 | if (first != list) {
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| 134 | struct list_head *last = list->prev;
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| 135 | struct list_head *at = head->next;
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| 136 |
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| 137 | first->prev = head;
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| 138 | head->next = first;
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| 139 |
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| 140 | last->next = at;
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| 141 | at->prev = last;
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| 142 | }
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| 143 | }
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| 144 |
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| 145 | /**
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| 146 | * list_entry - get the struct for this entry
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| 147 | * @ptr: the &struct list_head pointer.
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| 148 | * @type: the type of the struct this is embedded in.
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| 149 | * @member: the name of the list_struct within the struct.
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| 150 | */
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| 151 | #define list_entry(ptr, type, member) \
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| 152 | ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
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| 153 |
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| 154 | /**
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| 155 | * list_for_each - iterate over elements in a list
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| 156 | * @pos: the &struct list_head to use as a loop counter.
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| 157 | * @head: the head for your list.
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| 158 | */
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| 159 | #define list_for_each(pos, head) \
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| 160 | for (pos = (head)->next; pos != (head); pos = pos->next)
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| 161 |
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| 162 | /**
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| 163 | * list_for_each_safe - iterate over elements in a list, but don't dereference
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| 164 | * pos after the body is done (in case it is freed)
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| 165 | * @pos: the &struct list_head to use as a loop counter.
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| 166 | * @pnext: the &struct list_head to use as a pointer to the next item.
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| 167 | * @head: the head for your list (not included in iteration).
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| 168 | */
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| 169 | #define list_for_each_safe(pos, pnext, head) \
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| 170 | for (pos = (head)->next, pnext = pos->next; pos != (head); \
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| 171 | pos = pnext, pnext = pos->next)
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| 172 |
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| 173 | #undef _INLINE_
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| 174 |
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| 175 | #ifdef __cplusplus
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| 176 | }
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| 177 | #endif
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| 178 |
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| 179 | #endif /* _BLKID_LIST_H */
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