+++ /dev/null
-#ifndef _URCU_RCULFSTACK_STATIC_H
-#define _URCU_RCULFSTACK_STATIC_H
-
-/*
- * rculfstack-static.h
- *
- * Userspace RCU library - Lock-Free RCU Stack
- *
- * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See rculfstack.h for linking
- * dynamically with the userspace rcu library.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <urcu/uatomic.h>
-#include <urcu-pointer.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-static inline
-void _cds_lfs_node_init_rcu(struct cds_lfs_node_rcu *node)
-{
-}
-
-static inline
-void _cds_lfs_init_rcu(struct cds_lfs_stack_rcu *s)
-{
- s->head = NULL;
-}
-
-/*
- * Lock-free stack push is not subject to ABA problem, so no need to
- * take the RCU read-side lock. Even if "head" changes between two
- * uatomic_cmpxchg() invocations here (being popped, and then pushed
- * again by one or more concurrent threads), the second
- * uatomic_cmpxchg() invocation only cares about pushing a new entry at
- * the head of the stack, ensuring consistency by making sure the new
- * node->next is the same pointer value as the value replaced as head.
- * It does not care about the content of the actual next node, so it can
- * very well be reallocated between the two uatomic_cmpxchg().
- *
- * We take the approach of expecting the stack to be usually empty, so
- * we first try an initial uatomic_cmpxchg() on a NULL old_head, and
- * retry if the old head was non-NULL (the value read by the first
- * uatomic_cmpxchg() is used as old head for the following loop). The
- * upside of this scheme is to minimize the amount of cacheline traffic,
- * always performing an exclusive cacheline access, rather than doing
- * non-exclusive followed by exclusive cacheline access (which would be
- * required if we first read the old head value). This design decision
- * might be revisited after more throrough benchmarking on various
- * platforms.
- *
- * Returns 0 if the stack was empty prior to adding the node.
- * Returns non-zero otherwise.
- */
-static inline
-int _cds_lfs_push_rcu(struct cds_lfs_stack_rcu *s,
- struct cds_lfs_node_rcu *node)
-{
- struct cds_lfs_node_rcu *head = NULL;
-
- for (;;) {
- struct cds_lfs_node_rcu *old_head = head;
-
- node->next = head;
- /*
- * uatomic_cmpxchg() implicit memory barrier orders earlier
- * stores to node before publication.
- */
- head = uatomic_cmpxchg(&s->head, old_head, node);
- if (old_head == head)
- break;
- }
- return (int) !!((unsigned long) head);
-}
-
-/*
- * Should be called under rcu read-side lock.
- *
- * The caller must wait for a grace period to pass before freeing the returned
- * node or modifying the cds_lfs_node_rcu structure.
- * Returns NULL if stack is empty.
- */
-static inline
-struct cds_lfs_node_rcu *
-_cds_lfs_pop_rcu(struct cds_lfs_stack_rcu *s)
-{
- for (;;) {
- struct cds_lfs_node_rcu *head;
-
- head = rcu_dereference(s->head);
- if (head) {
- struct cds_lfs_node_rcu *next = rcu_dereference(head->next);
-
- if (uatomic_cmpxchg(&s->head, head, next) == head) {
- return head;
- } else {
- /* Concurrent modification. Retry. */
- continue;
- }
- } else {
- /* Empty stack */
- return NULL;
- }
- }
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* _URCU_RCULFSTACK_STATIC_H */
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