urcu/lfstack.h

   1 #ifndef _URCU_LFSTACK_H
   2 #define _URCU_LFSTACK_H
   3
   4 /*
   5  * lfstack.h
   6  *
   7  * Userspace RCU library - Lock-Free Stack
   8  *
   9  * Copyright 2010-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2.1 of the License, or (at your option) any later version.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 #ifdef __cplusplus
  27 extern "C" {
  28 #endif
  29
  30 struct cds_lfs_node {
  31         struct cds_lfs_node *next;
  32 };
  33
  34 struct cds_lfs_stack {
  35         struct cds_lfs_node *head;
  36 };
  37
  38 #ifdef _LGPL_SOURCE
  39
  40 #include <urcu/static/lfstack.h>
  41
  42 #define cds_lfs_node_init               _cds_lfs_node_init
  43 #define cds_lfs_init                    _cds_lfs_init
  44 #define cds_lfs_push                    _cds_lfs_push
  45 #define cds_lfs_pop                     _cds_lfs_pop
  46
  47 #else /* !_LGPL_SOURCE */
  48
  49 extern void cds_lfs_node_init(struct cds_lfs_node *node);
  50 extern void cds_lfs_init(struct cds_lfs_stack *s);
  51
  52 /*
  53  * cds_lfs_push: push a node into the stack.
  54  *
  55  * Does not require any synchronization with other push nor pop.
  56  *
  57  * Returns 0 if the stack was empty prior to adding the node.
  58  * Returns non-zero otherwise.
  59  */
  60 extern int cds_lfs_push(struct cds_lfs_stack *s,
  61                         struct cds_lfs_node *node);
  62
  63 /*
  64  * cds_lfs_pop: pop a node from the stack.
  65  *
  66  * Returns NULL if stack is empty.
  67  *
  68  * cds_lfs_pop needs to be synchronized using one of the following
  69  * techniques:
  70  *
  71  * 1) Calling cds_lfs_pop under rcu read lock critical section. The
  72  *    caller must wait for a grace period to pass before freeing the
  73  *    returned node or modifying the cds_lfs_node structure.
  74  * 2) Using mutual exclusion (e.g. mutexes) to protect cds_lfs_pop
  75  *    callers.
  76  * 3) Ensuring that only ONE thread can call cds_lfs_pop().
  77  *    (multi-provider/single-consumer scheme).
  78  */
  79 extern struct cds_lfs_node *cds_lfs_pop(struct cds_lfs_stack *s);
  80
  81 #endif /* !_LGPL_SOURCE */
  82
  83 #ifdef __cplusplus
  84 }
  85 #endif
  86
  87 #endif /* _URCU_LFSTACK_H */