From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 1 Sep 2011 13:31:55 +0000 (-0400)
Subject: wfstack: push returns prior stack emptiness state
X-Git-Tag: v0.6.5~40
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=191098fce0abcec4713428d402c9a892fe79bb77;p=userspace-rcu.git

wfstack: push returns prior stack emptiness state

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/urcu/static/wfstack.h b/urcu/static/wfstack.h
index 79ed3f7..cb68a59 100644
--- a/urcu/static/wfstack.h
+++ b/urcu/static/wfstack.h
@@ -56,8 +56,11 @@ void _cds_wfs_init(struct cds_wfs_stack *s)
 	assert(!ret);
 }
 
+/*
+ * Returns 0 if stack was empty, 1 otherwise.
+ */
 static inline
-void _cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node)
+int _cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node)
 {
 	struct cds_wfs_node *old_head;
 
@@ -72,6 +75,7 @@ void _cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node)
 	 * until node->next is set to old_head.
 	 */
 	CMM_STORE_SHARED(node->next, old_head);
+	return (old_head != CDS_WF_STACK_END);
 }
 
 /*
diff --git a/urcu/wfstack.h b/urcu/wfstack.h
index 354646d..db2ee0c 100644
--- a/urcu/wfstack.h
+++ b/urcu/wfstack.h
@@ -54,7 +54,7 @@ struct cds_wfs_stack {
 
 extern void cds_wfs_node_init(struct cds_wfs_node *node);
 extern void cds_wfs_init(struct cds_wfs_stack *s);
-extern void cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node);
+extern int cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node);
 /* __cds_wfs_pop_blocking: caller ensures mutual exclusion between pops */
 extern struct cds_wfs_node *__cds_wfs_pop_blocking(struct cds_wfs_stack *s);
 extern struct cds_wfs_node *cds_wfs_pop_blocking(struct cds_wfs_stack *s);
diff --git a/wfstack.c b/wfstack.c
index d999a5b..e9799e6 100644
--- a/wfstack.c
+++ b/wfstack.c
@@ -38,9 +38,9 @@ void cds_wfs_init(struct cds_wfs_stack *s)
 	_cds_wfs_init(s);
 }
 
-void cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node)
+int cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node)
 {
-	_cds_wfs_push(s, node);
+	return _cds_wfs_push(s, node);
 }
 
 struct cds_wfs_node *__cds_wfs_pop_blocking(struct cds_wfs_stack *s)