list.h

   1 /* Stolen from Linux Kernel Source's list.h -- GPL. */
   2 #ifndef _MODINITTOOLS_LIST_H
   3 #define _MODINITTOOLS_LIST_H
   4
   5 #undef offsetof
   6 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
   7
   8 /**
   9  * container_of - cast a member of a structure out to the containing structure
  10  *
  11  * @ptr:        the pointer to the member.
  12  * @type:       the type of the container struct this is embedded in.
  13  * @member:     the name of the member within the struct.
  14  *
  15  */
  16 #define container_of(ptr, type, member) ({                      \
  17         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
  18         (type *)( (char *)__mptr - offsetof(type,member) );})
  19
  20 /*
  21  * Simple doubly linked list implementation.
  22  *
  23  * Some of the internal functions ("__xxx") are useful when
  24  * manipulating whole lists rather than single entries, as
  25  * sometimes we already know the next/prev entries and we can
  26  * generate better code by using them directly rather than
  27  * using the generic single-entry routines.
  28  */
  29
  30 struct list_head {
  31         struct list_head *next, *prev;
  32 };
  33
  34 #define LIST_HEAD_INIT(name) { &(name), &(name) }
  35
  36 #define LIST_HEAD(name) \
  37         struct list_head name = LIST_HEAD_INIT(name)
  38
  39 #define INIT_LIST_HEAD(ptr) do { \
  40         (ptr)->next = (ptr); (ptr)->prev = (ptr); \
  41 } while (0)
  42
  43 /*
  44  * Insert a new entry between two known consecutive entries.
  45  *
  46  * This is only for internal list manipulation where we know
  47  * the prev/next entries already!
  48  */
  49 static inline void __list_add(struct list_head *new,
  50                               struct list_head *prev,
  51                               struct list_head *next)
  52 {
  53         next->prev = new;
  54         new->next = next;
  55         new->prev = prev;
  56         prev->next = new;
  57 }
  58
  59 /**
  60  * list_add - add a new entry
  61  * @new: new entry to be added
  62  * @head: list head to add it after
  63  *
  64  * Insert a new entry after the specified head.
  65  * This is good for implementing stacks.
  66  */
  67 static inline void list_add(struct list_head *new, struct list_head *head)
  68 {
  69         __list_add(new, head, head->next);
  70 }
  71
  72 /**
  73  * list_add_tail - add a new entry
  74  * @new: new entry to be added
  75  * @head: list head to add it before
  76  *
  77  * Insert a new entry before the specified head.
  78  * This is useful for implementing queues.
  79  */
  80 static inline void list_add_tail(struct list_head *new, struct list_head *head)
  81 {
  82         __list_add(new, head->prev, head);
  83 }
  84
  85 /*
  86  * Delete a list entry by making the prev/next entries
  87  * point to each other.
  88  *
  89  * This is only for internal list manipulation where we know
  90  * the prev/next entries already!
  91  */
  92 static inline void __list_del(struct list_head * prev, struct list_head * next)
  93 {
  94         next->prev = prev;
  95         prev->next = next;
  96 }
  97
  98 /**
  99  * list_del - deletes entry from list.
 100  * @entry: the element to delete from the list.
 101  * Note: list_empty on entry does not return true after this, the entry is
 102  * in an undefined state.
 103  */
 104 static inline void list_del(struct list_head *entry)
 105 {
 106         __list_del(entry->prev, entry->next);
 107 }
 108
 109 /**
 110  * list_del_init - deletes entry from list and reinitialize it.
 111  * @entry: the element to delete from the list.
 112  */
 113 static inline void list_del_init(struct list_head *entry)
 114 {
 115         __list_del(entry->prev, entry->next);
 116         INIT_LIST_HEAD(entry);
 117 }
 118
 119 /**
 120  * list_move - delete from one list and add as another's head
 121  * @list: the entry to move
 122  * @head: the head that will precede our entry
 123  */
 124 static inline void list_move(struct list_head *list, struct list_head *head)
 125 {
 126         __list_del(list->prev, list->next);
 127         list_add(list, head);
 128 }
 129
 130 /**
 131  * list_move_tail - delete from one list and add as another's tail
 132  * @list: the entry to move
 133  * @head: the head that will follow our entry
 134  */
 135 static inline void list_move_tail(struct list_head *list,
 136                                   struct list_head *head)
 137 {
 138         __list_del(list->prev, list->next);
 139         list_add_tail(list, head);
 140 }
 141
 142 /**
 143  * list_empty - tests whether a list is empty
 144  * @head: the list to test.
 145  */
 146 static inline int list_empty(struct list_head *head)
 147 {
 148         return head->next == head;
 149 }
 150
 151 static inline void __list_splice(struct list_head *list,
 152                                  struct list_head *head)
 153 {
 154         struct list_head *first = list->next;
 155         struct list_head *last = list->prev;
 156         struct list_head *at = head->next;
 157
 158         first->prev = head;
 159         head->next = first;
 160
 161         last->next = at;
 162         at->prev = last;
 163 }
 164
 165 /**
 166  * list_splice - join two lists
 167  * @list: the new list to add.
 168  * @head: the place to add it in the first list.
 169  */
 170 static inline void list_splice(struct list_head *list, struct list_head *head)
 171 {
 172         if (!list_empty(list))
 173                 __list_splice(list, head);
 174 }
 175
 176 /**
 177  * list_splice_init - join two lists and reinitialise the emptied list.
 178  * @list: the new list to add.
 179  * @head: the place to add it in the first list.
 180  *
 181  * The list at @list is reinitialised
 182  */
 183 static inline void list_splice_init(struct list_head *list,
 184                                     struct list_head *head)
 185 {
 186         if (!list_empty(list)) {
 187                 __list_splice(list, head);
 188                 INIT_LIST_HEAD(list);
 189         }
 190 }
 191
 192 /**
 193  * list_entry - get the struct for this entry
 194  * @ptr:        the &struct list_head pointer.
 195  * @type:       the type of the struct this is embedded in.
 196  * @member:     the name of the list_struct within the struct.
 197  */
 198 #define list_entry(ptr, type, member) \
 199         container_of(ptr, type, member)
 200
 201 /**
 202  * list_for_each        -       iterate over a list
 203  * @pos:        the &struct list_head to use as a loop counter.
 204  * @head:       the head for your list.
 205  */
 206 #define list_for_each(pos, head) \
 207         for (pos = (head)->next; pos != (head); pos = pos->next)
 208
 209 /**
 210  * list_for_each_prev   -       iterate over a list backwards
 211  * @pos:        the &struct list_head to use as a loop counter.
 212  * @head:       the head for your list.
 213  */
 214 #define list_for_each_prev(pos, head) \
 215         for (pos = (head)->prev; pos != (head); pos = pos->prev)
 216
 217 /**
 218  * list_for_each_safe   -       iterate over a list safe against removal of list entry
 219  * @pos:        the &struct list_head to use as a loop counter.
 220  * @n:          another &struct list_head to use as temporary storage
 221  * @head:       the head for your list.
 222  */
 223 #define list_for_each_safe(pos, n, head) \
 224         for (pos = (head)->next, n = pos->next; pos != (head); \
 225                 pos = n, n = pos->next)
 226
 227 /**
 228  * list_for_each_entry  -       iterate over list of given type
 229  * @pos:        the type * to use as a loop counter.
 230  * @head:       the head for your list.
 231  * @member:     the name of the list_struct within the struct.
 232  */
 233 #define list_for_each_entry(pos, head, member)                          \
 234         for (pos = list_entry((head)->next, typeof(*pos), member);      \
 235              &pos->member != (head);                                    \
 236              pos = list_entry(pos->member.next, typeof(*pos), member))
 237
 238 #endif