X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=urcu%2Frculfstack-static.h;fp=urcu%2Frculfstack-static.h;h=8eae35d1bc0d2c9fc12955d6c5185f3bcb1ecfbb;hb=b6a37eaca5f072e7bba90a2562b7f2ac238fe23b;hp=0000000000000000000000000000000000000000;hpb=3d02c34dba0edc4a3554a3862a2ae96d77b3b4e8;p=urcu.git

diff --git a/urcu/rculfstack-static.h b/urcu/rculfstack-static.h
new file mode 100644
index 0000000..8eae35d
--- /dev/null
+++ b/urcu/rculfstack-static.h
@@ -0,0 +1,104 @@
+#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_arch.h>
+/* A urcu implementation header should be already included. */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void _rcu_lfs_node_init(struct rcu_lfs_node *node)
+{
+}
+
+void _rcu_lfs_init(struct rcu_lfs_stack *s)
+{
+	s->head = NULL;
+}
+
+void _rcu_lfs_push(struct rcu_lfs_stack *s, struct rcu_lfs_node *node)
+{
+	for (;;) {
+		struct rcu_lfs_node *head;
+
+		rcu_read_lock();
+		head = rcu_dereference(s->head);
+		node->next = head;
+		/*
+		 * uatomic_cmpxchg() implicit memory barrier orders earlier
+		 * stores to node before publication.
+		 */
+		if (uatomic_cmpxchg(&s->head, head, node) == head) {
+			rcu_read_unlock();
+			return;
+		} else {
+			/* Failure to prepend. Retry. */
+			rcu_read_unlock();
+			continue;
+		}
+	}
+}
+
+/*
+ * The caller must wait for a grace period to pass before freeing the returned
+ * node or modifying the rcu_lfs_node structure.
+ * Returns NULL if stack is empty.
+ */
+struct rcu_lfs_node *
+_rcu_lfs_pop(struct rcu_lfs_stack *s)
+{
+	for (;;) {
+		struct rcu_lfs_node *head;
+
+		rcu_read_lock();
+		head = rcu_dereference(s->head);
+		if (head) {
+			struct rcu_lfs_node *next = rcu_dereference(head->next);
+
+			if (uatomic_cmpxchg(&s->head, head, next) == head) {
+				rcu_read_unlock();
+				return head;
+			} else {
+				/* Concurrent modification. Retry. */
+				rcu_read_unlock();
+				continue;
+			}
+		} else {
+			/* Empty stack */
+			rcu_read_unlock();
+			return NULL;
+		}
+	}
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _URCU_RCULFSTACK_STATIC_H */