urcu/rculist.h

   1 /*
   2  * Copyright (C) 2002 Free Software Foundation, Inc.
   3  * (originally part of the GNU C Library)
   4  * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   5  *
   6  * Copyright (C) 2009 Pierre-Marc Fournier
   7  * Conversion to RCU list.
   8  * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with this library; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #ifndef _URCU_RCULIST_H
  26 #define _URCU_RCULIST_H
  27
  28 #include <urcu/list.h>
  29 #include <urcu/arch.h>
  30 #include <urcu-pointer.h>
  31
  32 /* Add new element at the head of the list. */
  33 static inline
  34 void cds_list_add_rcu(struct cds_list_head *newp, struct cds_list_head *head)
  35 {
  36         newp->next = head->next;
  37         newp->prev = head;
  38         head->next->prev = newp;
  39         rcu_assign_pointer(head->next, newp);
  40 }
  41
  42 /* Add new element at the tail of the list. */
  43 static inline
  44 void cds_list_add_tail_rcu(struct cds_list_head *newp,
  45                 struct cds_list_head *head)
  46 {
  47         newp->next = head;
  48         newp->prev = head->prev;
  49         rcu_assign_pointer(head->prev->next, newp);
  50         head->prev = newp;
  51 }
  52
  53 /*
  54  * Replace an old entry atomically with respect to concurrent RCU
  55  * traversal. Mutual exclusion against concurrent updates is required
  56  * though.
  57  */
  58 static inline
  59 void cds_list_replace_rcu(struct cds_list_head *old, struct cds_list_head *_new)
  60 {
  61         _new->next = old->next;
  62         _new->prev = old->prev;
  63         rcu_assign_pointer(_new->prev->next, _new);
  64         _new->next->prev = _new;
  65 }
  66
  67 /* Remove element from list. */
  68 static inline
  69 void cds_list_del_rcu(struct cds_list_head *elem)
  70 {
  71         elem->next->prev = elem->prev;
  72         CMM_STORE_SHARED(elem->prev->next, elem->next);
  73 }
  74
  75 /*
  76  * Iteration through all elements of the list must be done while rcu_read_lock()
  77  * is held.
  78  */
  79
  80 /* Iterate forward over the elements of the list.  */
  81 #define cds_list_for_each_rcu(pos, head) \
  82         for (pos = rcu_dereference((head)->next); pos != (head); \
  83                 pos = rcu_dereference(pos->next))
  84
  85
  86 /* Iterate through elements of the list. */
  87 #define cds_list_for_each_entry_rcu(pos, head, member) \
  88         for (pos = cds_list_entry(rcu_dereference((head)->next), __typeof__(*pos), member); \
  89                 &pos->member != (head); \
  90                 pos = cds_list_entry(rcu_dereference(pos->member.next), __typeof__(*pos), member))
  91
  92 #endif  /* _URCU_RCULIST_H */