urcu/rcuhlist.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_RCUHLIST_H
  26 #define _URCU_RCUHLIST_H
  27
  28 #include <urcu/hlist.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_hlist_add_head_rcu(struct cds_hlist_node *newp,
  35                 struct cds_hlist_head *head)
  36 {
  37         newp->next = head->next;
  38         newp->prev = (struct cds_hlist_node *)head;
  39         if (head->next)
  40                 head->next->prev = newp;
  41         rcu_assign_pointer(head->next, newp);
  42 }
  43
  44 /* Remove element from list. */
  45 static inline
  46 void cds_hlist_del_rcu(struct cds_hlist_node *elem)
  47 {
  48         if (elem->next)
  49                 elem->next->prev = elem->prev;
  50         CMM_STORE_SHARED(elem->prev->next, elem->next);
  51 }
  52
  53 /*
  54  * Iterate through elements of the list.
  55  * This must be done while rcu_read_lock() is held.
  56  */
  57 #define cds_hlist_for_each_rcu(pos, head) \
  58         for (pos = rcu_dereference((head)->next); pos != NULL; \
  59                 pos = rcu_dereference(pos->next))
  60
  61 /*
  62  * cds_hlist_for_each_entry_rcu takes 4 arguments, while the Linux
  63  * kernel API only takes 3.
  64  * We implement cds_hlist_for_each_entry_rcu_2() to follow the Linux
  65  * kernel APIs.
  66  */
  67 #define cds_hlist_for_each_entry_rcu(entry, pos, head, member) \
  68         for (pos = rcu_dereference((head)->next), \
  69                         entry = cds_hlist_entry(pos, __typeof__(*entry), member); \
  70                 pos != NULL; \
  71                 pos = rcu_dereference(pos->next), \
  72                         entry = cds_hlist_entry(pos, __typeof__(*entry), member))
  73
  74 #define cds_hlist_for_each_entry_rcu_2(entry, head, member) \
  75         for (entry = cds_hlist_entry(rcu_dereference((head)->next), \
  76                         __typeof__(*entry), member); \
  77                 &entry->member != NULL; \
  78                 entry = cds_hlist_entry(rcu_dereference(entry->member.next), \
  79                         __typeof__(*entry), member))
  80
  81 #endif  /* _URCU_RCUHLIST_H */