urcu/hlist.h

   1 #ifndef _KCOMPAT_HLIST_H
   2 #define _KCOMPAT_HLIST_H
   3
   4 /*
   5  * Kernel sourcecode compatible lightweight single pointer list head useful
   6  * for implementing hash tables
   7  *
   8  * Copyright (C) 2009 Novell Inc.
   9  *
  10  * Author: Jan Blunck <jblunck@suse.de>
  11  *
  12  * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  13  *
  14  * This program is free software; you can redistribute it and/or modify it
  15  * under the terms of the GNU Lesser General Public License version 2.1 as
  16  * published by the Free  Software Foundation.
  17  */
  18
  19 struct hlist_head
  20 {
  21         struct hlist_node *next;
  22 };
  23
  24 struct hlist_node
  25 {
  26         struct hlist_node *next;
  27         struct hlist_node *prev;
  28 };
  29
  30 /* Initialize a new list head.  */
  31 static inline void  INIT_HLIST_HEAD(struct hlist_head *ptr)
  32 {
  33         ptr->next = NULL;
  34 }
  35
  36 /* Get typed element from list at a given position.  */
  37 #define hlist_entry(ptr, type, member)                                  \
  38         ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
  39
  40 /* Add new element at the head of the list.  */
  41 static inline void hlist_add_head (struct hlist_node *newp,
  42                                    struct hlist_head *head)
  43 {
  44         if (head->next)
  45                 head->next->prev = newp;
  46
  47         newp->next = head->next;
  48         newp->prev = (struct hlist_node *)head;
  49         head->next = newp;
  50 }
  51
  52 /* Remove element from list.  */
  53 static inline void hlist_del (struct hlist_node *elem)
  54 {
  55         if (elem->next)
  56                 elem->next->prev = elem->prev;
  57
  58         elem->prev->next = elem->next;
  59 }
  60
  61 #define hlist_for_each_entry(entry, pos, head, member)                  \
  62         for (pos = (head)->next,                                        \
  63                      entry = hlist_entry(pos, typeof(*entry), member);  \
  64              pos != NULL;                                               \
  65              pos = pos->next,                                   \
  66                      entry = hlist_entry(pos, typeof(*entry), member))
  67
  68 #define hlist_for_each_entry_safe(entry, pos, p, head, member)          \
  69         for (pos = (head)->next,                                        \
  70                      entry = hlist_entry(pos, typeof(*entry), member);  \
  71              (pos != NULL) && ({ p = pos->next; 1;});                   \
  72              pos = p,                                                   \
  73                      entry = hlist_entry(pos, typeof(*entry), member))
  74
  75 #endif  /* _KCOMPAT_HLIST_H */