include/urcu/rcuhlist.h

   1 // SPDX-FileCopyrightText: 2002 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_RCUHLIST_H
  13 #define _URCU_RCUHLIST_H
  14
  15 #include <urcu/hlist.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_hlist_add_head_rcu(struct cds_hlist_node *newp,
  22                 struct cds_hlist_head *head)
  23 {
  24         newp->next = head->next;
  25         newp->prev = (struct cds_hlist_node *)head;
  26         if (head->next)
  27                 head->next->prev = newp;
  28         rcu_assign_pointer(head->next, newp);
  29 }
  30
  31 /* Remove element from list. */
  32 static inline
  33 void cds_hlist_del_rcu(struct cds_hlist_node *elem)
  34 {
  35         if (elem->next)
  36                 elem->next->prev = elem->prev;
  37         CMM_STORE_SHARED(elem->prev->next, elem->next);
  38 }
  39
  40 /*
  41  * Iterate through elements of the list.
  42  * This must be done while rcu_read_lock() is held.
  43  */
  44 #define cds_hlist_for_each_rcu(pos, head) \
  45         for (pos = rcu_dereference((head)->next); (pos) != NULL; \
  46                 pos = rcu_dereference((pos)->next))
  47
  48 /*
  49  * cds_hlist_for_each_entry_rcu takes 4 arguments, while the Linux
  50  * kernel API only takes 3.
  51  * We implement cds_hlist_for_each_entry_rcu_2() to follow the Linux
  52  * kernel APIs.
  53  */
  54 #define cds_hlist_for_each_entry_rcu(entry, pos, head, member) \
  55         for (pos = rcu_dereference((head)->next), \
  56                         entry = cds_hlist_entry(pos, __typeof__(*(entry)), member); \
  57                 (pos) != NULL; \
  58                 pos = rcu_dereference((pos)->next), \
  59                         entry = cds_hlist_entry(pos, __typeof__(*(entry)), member))
  60
  61 #define cds_hlist_for_each_entry_rcu_2(entry, head, member) \
  62         for (entry = cds_hlist_entry_safe(rcu_dereference((head)->next), \
  63                         __typeof__(*(entry)), member); \
  64                 (entry) != NULL; \
  65                 entry = cds_hlist_entry_safe(rcu_dereference((entry)->member.next), \
  66                         __typeof__(*(entry)), member))
  67
  68 #endif  /* _URCU_RCUHLIST_H */