include/urcu/rculist.h

   1 // SPDX-FileCopyrightText: Free Software Foundation, Inc.
   2 // SPDX-FileCopyrightText: 2009 Pierre-Marc Fournier
   3 // SPDX-FileCopyrightText: 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4 //
   5 // SPDX-License-Identifier: LGPL-2.1-or-later
   6
   7 /*
   8  * (originally part of the GNU C Library)
   9  * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
  10  */
  11
  12 #ifndef _URCU_RCULIST_H
  13 #define _URCU_RCULIST_H
  14
  15 #include <urcu/list.h>
  16 #include <urcu/arch.h>
  17 #include <urcu-pointer.h>
  18
  19 /* Add new element at the head of the list. */
  20 static inline
  21 void cds_list_add_rcu(struct cds_list_head *newp, struct cds_list_head *head)
  22 {
  23         newp->next = head->next;
  24         newp->prev = head;
  25         head->next->prev = newp;
  26         rcu_assign_pointer(head->next, newp);
  27 }
  28
  29 /* Add new element at the tail of the list. */
  30 static inline
  31 void cds_list_add_tail_rcu(struct cds_list_head *newp,
  32                 struct cds_list_head *head)
  33 {
  34         newp->next = head;
  35         newp->prev = head->prev;
  36         rcu_assign_pointer(head->prev->next, newp);
  37         head->prev = newp;
  38 }
  39
  40 /*
  41  * Replace an old entry atomically with respect to concurrent RCU
  42  * traversal. Mutual exclusion against concurrent updates is required
  43  * though.
  44  */
  45 static inline
  46 void cds_list_replace_rcu(struct cds_list_head *old, struct cds_list_head *_new)
  47 {
  48         _new->next = old->next;
  49         _new->prev = old->prev;
  50         rcu_assign_pointer(_new->prev->next, _new);
  51         _new->next->prev = _new;
  52 }
  53
  54 /* Remove element from list. */
  55 static inline
  56 void cds_list_del_rcu(struct cds_list_head *elem)
  57 {
  58         elem->next->prev = elem->prev;
  59         CMM_STORE_SHARED(elem->prev->next, elem->next);
  60 }
  61
  62 /*
  63  * Iteration through all elements of the list must be done while rcu_read_lock()
  64  * is held.
  65  */
  66
  67 /* Iterate forward over the elements of the list.  */
  68 #define cds_list_for_each_rcu(pos, head) \
  69         for (pos = rcu_dereference((head)->next); (pos) != (head); \
  70                 pos = rcu_dereference((pos)->next))
  71
  72 /* Iterate through elements of the list. */
  73 #define cds_list_for_each_entry_rcu(pos, head, member) \
  74         for (pos = cds_list_entry(rcu_dereference((head)->next), __typeof__(*(pos)), member); \
  75                 &(pos)->member != (head); \
  76                 pos = cds_list_entry(rcu_dereference((pos)->member.next), __typeof__(*(pos)), member))
  77
  78 #endif  /* _URCU_RCULIST_H */