firmware/export/linkedlist.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) by Linux Kernel Developers
  11  *
  12  * Original source can be found in linux kernel: <kernel>/include/list.h
  13  *
  14  * All files in this archive are subject to the GNU General Public License.
  15  * See the file COPYING in the source tree root for full license agreement.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #ifndef _LINKED_LIST_H_
  23 #define _LINKED_LIST_H_
  24
  25 #include <stddef.h> /* used for offsetof */
  26
  27 static inline void prefetch(const void *x) { (void)x; }
  28
  29 /*
  30  * Simple doubly linked list implementation.
  31  *
  32  * Some of the internal functions ("__xxx") are useful when
  33  * manipulating whole lists rather than single entries, as
  34  * sometimes we already know the next/prev entries and we can
  35  * generate better code by using them directly rather than
  36  * using the generic single-entry routines.
  37  */
  38
  39 /* TODO move this macro? */
  40 /* more about this macro: http://www.kroah.com/log/linux/container_of.html */
  41 #define container_of(ptr, type, member) ({ \
  42                 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
  43                 (type *)( (char *)__mptr - offsetof(type,member) );})
  44
  45 /*
  46  * These are non-NULL pointers that will result in page faults
  47  * under normal circumstances, used to verify that nobody uses
  48  * non-initialized list entries.
  49  */
  50 #define LIST_POISON1  ((void *) 0x00100100)
  51 #define LIST_POISON2  ((void *) 0x00200200)
  52
  53 struct list_head {
  54     struct list_head *next, *prev;
  55 };
  56
  57 #define LIST_HEAD_INIT(name) { &(name), &(name) }
  58
  59 #define LIST_HEAD(name) \
  60     struct list_head name = LIST_HEAD_INIT(name)
  61
  62 static inline void INIT_LIST_HEAD(struct list_head *list)
  63 {
  64     list->next = list;
  65     list->prev = list;
  66 }
  67
  68 /*
  69  * Insert a new entry between two known consecutive entries.
  70  *
  71  * This is only for internal list manipulation where we know
  72  * the prev/next entries already!
  73  */
  74 static inline void __list_add(struct list_head *new,
  75                               struct list_head *prev,
  76                               struct list_head *next)
  77 {
  78     next->prev = new;
  79     new->next = next;
  80     new->prev = prev;
  81     prev->next = new;
  82 }
  83
  84
  85 /**
  86  * list_add - add a new entry
  87  * @new: new entry to be added
  88  * @head: list head to add it after
  89  *
  90  * Insert a new entry after the specified head.
  91  * This is good for implementing stacks.
  92  */
  93 static inline void list_add(struct list_head *new, struct list_head *head)
  94 {
  95     __list_add(new, head, head->next);
  96 }
  97
  98
  99 /**
 100  * list_add_tail - add a new entry
 101  * @new: new entry to be added
 102  * @head: list head to add it before
 103  *
 104  * Insert a new entry before the specified head.
 105  * This is useful for implementing queues.
 106  */
 107 static inline void list_add_tail(struct list_head *new, struct list_head *head)
 108 {
 109     __list_add(new, head->prev, head);
 110 }
 111
 112 /*
 113  * Delete a list entry by making the prev/next entries
 114  * point to each other.
 115  *
 116  * This is only for internal list manipulation where we know
 117  * the prev/next entries already!
 118  */
 119 static inline void __list_del(struct list_head * prev, struct list_head * next)
 120 {
 121     next->prev = prev;
 122     prev->next = next;
 123 }
 124
 125 /**
 126  * list_del - deletes entry from list.
 127  * @entry: the element to delete from the list.
 128  * Note: list_empty() on entry does not return true after this, the entry is
 129  * in an undefined state.
 130  */
 131 static inline void list_del(struct list_head *entry)
 132 {
 133     __list_del(entry->prev, entry->next);
 134     entry->next = LIST_POISON1;
 135     entry->prev = LIST_POISON2;
 136 }
 137
 138 /**
 139  * list_replace - replace old entry by new one
 140  * @old : the element to be replaced
 141  * @new : the new element to insert
 142  *
 143  * If @old was empty, it will be overwritten.
 144  */
 145 static inline void list_replace(struct list_head *old,
 146                                 struct list_head *new)
 147 {
 148     new->next = old->next;
 149     new->next->prev = new;
 150     new->prev = old->prev;
 151     new->prev->next = new;
 152 }
 153
 154 static inline void list_replace_init(struct list_head *old,
 155                                      struct list_head *new)
 156 {
 157     list_replace(old, new);
 158     INIT_LIST_HEAD(old);
 159 }
 160
 161 /**
 162  * list_del_init - deletes entry from list and reinitialize it.
 163  * @entry: the element to delete from the list.
 164  */
 165 static inline void list_del_init(struct list_head *entry)
 166 {
 167     __list_del(entry->prev, entry->next);
 168     INIT_LIST_HEAD(entry);
 169 }
 170
 171 /**
 172  * list_move - delete from one list and add as another's head
 173  * @list: the entry to move
 174  * @head: the head that will precede our entry
 175  */
 176 static inline void list_move(struct list_head *list, struct list_head *head)
 177 {
 178     __list_del(list->prev, list->next);
 179     list_add(list, head);
 180 }
 181
 182 /**
 183  * list_move_tail - delete from one list and add as another's tail
 184  * @list: the entry to move
 185  * @head: the head that will follow our entry
 186  */
 187 static inline void list_move_tail(struct list_head *list,
 188                                   struct list_head *head)
 189 {
 190     __list_del(list->prev, list->next);
 191     list_add_tail(list, head);
 192 }
 193
 194 /**
 195  * list_is_last - tests whether @list is the last entry in list @head
 196  * @list: the entry to test
 197  * @head: the head of the list
 198  */
 199 static inline int list_is_last(const struct list_head *list,
 200                                const struct list_head *head)
 201 {
 202     return list->next == head;
 203 }
 204
 205 /**
 206  * list_empty - tests whether a list is empty
 207  * @head: the list to test.
 208  */
 209 static inline int list_empty(const struct list_head *head)
 210 {
 211     return head->next == head;
 212 }
 213
 214 static inline void __list_splice(struct list_head *list,
 215                                  struct list_head *head)
 216 {
 217     struct list_head *first = list->next;
 218     struct list_head *last = list->prev;
 219     struct list_head *at = head->next;
 220
 221     first->prev = head;
 222     head->next = first;
 223
 224     last->next = at;
 225     at->prev = last;
 226 }
 227
 228 /**
 229  * list_splice - join two lists
 230  * @list: the new list to add.
 231  * @head: the place to add it in the first list.
 232  */
 233 static inline void list_splice(struct list_head *list, struct list_head *head)
 234 {
 235     if (!list_empty(list)) {
 236         __list_splice(list, head);
 237     }
 238 }
 239
 240 /**
 241  * list_splice_init - join two lists and reinitialise the emptied list.
 242  * @list: the new list to add.
 243  * @head: the place to add it in the first list.
 244  *
 245  * The list at @list is reinitialised
 246  */
 247 static inline void list_splice_init(struct list_head *list,
 248                                     struct list_head *head)
 249 {
 250     if (!list_empty(list)) {
 251         __list_splice(list, head);
 252         INIT_LIST_HEAD(list);
 253     }
 254 }
 255
 256 /**
 257  * list_entry - get the struct for this entry
 258  * @ptr:        the &struct list_head pointer.
 259  * @type:       the type of the struct this is embedded in.
 260  * @member:     the name of the list_struct within the struct.
 261  */
 262 #define list_entry(ptr, type, member) \
 263     container_of(ptr, type, member)
 264
 265 /**
 266  * list_for_each - iterate over a list
 267  * @pos:        the &struct list_head to use as a loop cursor.
 268  * @head:       the head for your list.
 269  */
 270 #define list_for_each(pos, head) \
 271     for (pos = (head)->next; prefetch(pos->next), pos != (head); \
 272         pos = pos->next)
 273
 274 /**
 275  * __list_for_each - iterate over a list
 276  * @pos:    the &struct list_head to use as a loop cursor.
 277  * @head:   the head for your list.
 278  *
 279  * This variant differs from list_for_each() in that it's the
 280  * simplest possible list iteration code, no prefetching is done.
 281  * Use this for code that knows the list to be very short (empty
 282  * or 1 entry) most of the time.
 283  */
 284 #define __list_for_each(pos, head) \
 285     for (pos = (head)->next; pos != (head); pos = pos->next)
 286
 287 /**
 288  * list_for_each_prev - iterate over a list backwards
 289  * @pos:    the &struct list_head to use as a loop cursor.
 290  * @head:   the head for your list.
 291  */
 292 #define list_for_each_prev(pos, head) \
 293     for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
 294         pos = pos->prev)
 295
 296 /**
 297  * list_for_each_entry - iterate over list of given type
 298  * @pos:        the type * to use as a loop cursor.
 299  * @head:       the head for your list.
 300  * @member:     the name of the list_struct within the struct.
 301  */
 302 #define list_for_each_entry(pos, head, member)                  \
 303     for (pos = list_entry((head)->next, typeof(*pos), member);  \
 304         prefetch(pos->member.next), &pos->member != (head);     \
 305         pos = list_entry(pos->member.next, typeof(*pos), member))
 306
 307 /**
 308  * list_for_each_entry_reverse - iterate backwards over list of given type.
 309  * @pos:        the type * to use as a loop cursor.
 310  * @head:       the head for your list.
 311  * @member:     the name of the list_struct within the struct.
 312  */
 313 #define list_for_each_entry_reverse(pos, head, member)          \
 314     for (pos = list_entry((head)->prev, typeof(*pos), member);  \
 315         prefetch(pos->member.prev), &pos->member != (head);     \
 316         pos = list_entry(pos->member.prev, typeof(*pos), member))
 317
 318 /**
 319  * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
 320  * @pos:        the type * to use as a start point
 321  * @head:       the head of the list
 322  * @member:     the name of the list_struct within the struct.
 323  *
 324  * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
 325  */
 326 #define list_prepare_entry(pos, head, member) \
 327     ((pos) ? : list_entry(head, typeof(*pos), member))
 328
 329 /**
 330  * list_for_each_entry_continue - continue iteration over list of given type
 331  * @pos:        the type * to use as a loop cursor.
 332  * @head:       the head for your list.
 333  * @member:     the name of the list_struct within the struct.
 334  *
 335  * Continue to iterate over list of given type, continuing after
 336  * the current position.
 337  */
 338 #define list_for_each_entry_continue(pos, head, member)             \
 339     for (pos = list_entry(pos->member.next, typeof(*pos), member);  \
 340         prefetch(pos->member.next), &pos->member != (head);         \
 341         pos = list_entry(pos->member.next, typeof(*pos), member))
 342
 343 /**
 344  * list_for_each_entry_from - iterate over list of given type from the current point
 345  * @pos:        the type * to use as a loop cursor.
 346  * @head:       the head for your list.
 347  * @member:     the name of the list_struct within the struct.
 348  *
 349  * Iterate over list of given type, continuing from current position.
 350  */
 351 #define list_for_each_entry_from(pos, head, member)             \
 352     for (; prefetch(pos->member.next), &pos->member != (head);  \
 353         pos = list_entry(pos->member.next, typeof(*pos), member))
 354
 355 #endif /*_LINKED_LIST_H_*/