X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Fstatic%2Fwfstack.h;h=e96c8876a2b916dcd5bde1e1ba2ad3f8b5ff4ec8;hp=9bc9519f16f43c87a65974ad1697fecfb242d94e;hb=200d100e05ed8e10c47f971939042f2406df92ef;hpb=af67624df8d06ebaa5d72dd863a73d334611e900

diff --git a/urcu/static/wfstack.h b/urcu/static/wfstack.h
index 9bc9519..e96c887 100644
--- a/urcu/static/wfstack.h
+++ b/urcu/static/wfstack.h
@@ -77,7 +77,17 @@ void _cds_wfs_node_init(struct cds_wfs_node *node)
 }
 
 /*
- * cds_wfs_init: initialize wait-free stack.
+ * __cds_wfs_init: initialize wait-free stack. Don't pair with
+ * any destroy function.
+ */
+static inline void ___cds_wfs_init(struct __cds_wfs_stack *s)
+{
+	s->head = CDS_WFS_END;
+}
+
+/*
+ * cds_wfs_init: initialize wait-free stack. Pair with
+ * cds_wfs_destroy().
  */
 static inline
 void _cds_wfs_init(struct cds_wfs_stack *s)
@@ -89,6 +99,17 @@ void _cds_wfs_init(struct cds_wfs_stack *s)
 	assert(!ret);
 }
 
+/*
+ * cds_wfs_destroy: destroy wait-free stack. Pair with
+ * cds_wfs_init().
+ */
+static inline
+void _cds_wfs_destroy(struct cds_wfs_stack *s)
+{
+	int ret = pthread_mutex_destroy(&s->lock);
+	assert(!ret);
+}
+
 static inline bool ___cds_wfs_end(void *node)
 {
 	return node == CDS_WFS_END;
@@ -99,8 +120,10 @@ static inline bool ___cds_wfs_end(void *node)
  *
  * No memory barrier is issued. No mutual exclusion is required.
  */
-static inline bool _cds_wfs_empty(struct cds_wfs_stack *s)
+static inline bool _cds_wfs_empty(cds_wfs_stack_ptr_t u_stack)
 {
+	struct __cds_wfs_stack *s = u_stack._s;
+
 	return ___cds_wfs_end(CMM_LOAD_SHARED(s->head));
 }
 
@@ -114,8 +137,9 @@ static inline bool _cds_wfs_empty(struct cds_wfs_stack *s)
  * Returns non-zero otherwise.
  */
 static inline
-int _cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node)
+int _cds_wfs_push(cds_wfs_stack_ptr_t u_stack, struct cds_wfs_node *node)
 {
+	struct __cds_wfs_stack *s = u_stack._s;
 	struct cds_wfs_head *old_head, *new_head;
 
 	assert(node->next == NULL);
@@ -149,7 +173,7 @@ ___cds_wfs_node_sync_next(struct cds_wfs_node *node, int blocking)
 		if (!blocking)
 			return CDS_WFS_WOULDBLOCK;
 		if (++attempt >= CDS_WFS_ADAPT_ATTEMPTS) {
-			poll(NULL, 0, CDS_WFS_WAIT);	/* Wait for 10ms */
+			(void) poll(NULL, 0, CDS_WFS_WAIT);	/* Wait for 10ms */
 			attempt = 0;
 		} else {
 			caa_cpu_relax();
@@ -161,29 +185,38 @@ ___cds_wfs_node_sync_next(struct cds_wfs_node *node, int blocking)
 
 static inline
 struct cds_wfs_node *
-___cds_wfs_pop(struct cds_wfs_stack *s, int blocking)
+___cds_wfs_pop(cds_wfs_stack_ptr_t u_stack, int *state, int blocking)
 {
 	struct cds_wfs_head *head, *new_head;
 	struct cds_wfs_node *next;
+	struct __cds_wfs_stack *s = u_stack._s;
 
+	if (state)
+		*state = 0;
 	for (;;) {
 		head = CMM_LOAD_SHARED(s->head);
-		if (___cds_wfs_end(head))
+		if (___cds_wfs_end(head)) {
 			return NULL;
+		}
 		next = ___cds_wfs_node_sync_next(&head->node, blocking);
-		if (!blocking && next == CDS_WFS_WOULDBLOCK)
+		if (!blocking && next == CDS_WFS_WOULDBLOCK) {
 			return CDS_WFS_WOULDBLOCK;
+		}
 		new_head = caa_container_of(next, struct cds_wfs_head, node);
-		if (uatomic_cmpxchg(&s->head, head, new_head) == head)
+		if (uatomic_cmpxchg(&s->head, head, new_head) == head) {
+			if (state && ___cds_wfs_end(new_head))
+				*state |= CDS_WFS_STATE_LAST;
 			return &head->node;
-		if (!blocking)
+		}
+		if (!blocking) {
 			return CDS_WFS_WOULDBLOCK;
+		}
 		/* busy-loop if head changed under us */
 	}
 }
 
 /*
- * __cds_wfs_pop_blocking: pop a node from the stack.
+ * __cds_wfs_pop_with_state_blocking: pop a node from the stack, with state.
  *
  * Returns NULL if stack is empty.
  *
@@ -197,12 +230,36 @@ ___cds_wfs_pop(struct cds_wfs_stack *s, int blocking)
  *     __cds_wfs_pop_blocking and __cds_wfs_pop_all callers.
  * 3) Ensuring that only ONE thread can call __cds_wfs_pop_blocking()
  *    and __cds_wfs_pop_all(). (multi-provider/single-consumer scheme).
+ *
+ * "state" saves state flags atomically sampled with pop operation.
  */
 static inline
 struct cds_wfs_node *
-___cds_wfs_pop_blocking(struct cds_wfs_stack *s)
+___cds_wfs_pop_with_state_blocking(cds_wfs_stack_ptr_t u_stack, int *state)
 {
-	return ___cds_wfs_pop(s, 1);
+	return ___cds_wfs_pop(u_stack, state, 1);
+}
+
+static inline
+struct cds_wfs_node *
+___cds_wfs_pop_blocking(cds_wfs_stack_ptr_t u_stack)
+{
+	return ___cds_wfs_pop_with_state_blocking(u_stack, NULL);
+}
+
+/*
+ * __cds_wfs_pop_with_state_nonblocking: pop a node from the stack.
+ *
+ * Same as __cds_wfs_pop_with_state_blocking, but returns
+ * CDS_WFS_WOULDBLOCK if it needs to block.
+ *
+ * "state" saves state flags atomically sampled with pop operation.
+ */
+static inline
+struct cds_wfs_node *
+___cds_wfs_pop_with_state_nonblocking(cds_wfs_stack_ptr_t u_stack, int *state)
+{
+	return ___cds_wfs_pop(u_stack, state, 0);
 }
 
 /*
@@ -213,9 +270,9 @@ ___cds_wfs_pop_blocking(struct cds_wfs_stack *s)
  */
 static inline
 struct cds_wfs_node *
-___cds_wfs_pop_nonblocking(struct cds_wfs_stack *s)
+___cds_wfs_pop_nonblocking(cds_wfs_stack_ptr_t u_stack)
 {
-	return ___cds_wfs_pop(s, 0);
+	return ___cds_wfs_pop_with_state_nonblocking(u_stack, NULL);
 }
 
 /*
@@ -237,8 +294,9 @@ ___cds_wfs_pop_nonblocking(struct cds_wfs_stack *s)
  */
 static inline
 struct cds_wfs_head *
-___cds_wfs_pop_all(struct cds_wfs_stack *s)
+___cds_wfs_pop_all(cds_wfs_stack_ptr_t u_stack)
 {
+	struct __cds_wfs_stack *s = u_stack._s;
 	struct cds_wfs_head *head;
 
 	/*
@@ -280,20 +338,30 @@ static inline void _cds_wfs_pop_unlock(struct cds_wfs_stack *s)
 }
 
 /*
- * Call __cds_wfs_pop_blocking with an internal pop mutex held.
+ * Call __cds_wfs_pop_with_state_blocking with an internal pop mutex held.
  */
 static inline
 struct cds_wfs_node *
-_cds_wfs_pop_blocking(struct cds_wfs_stack *s)
+_cds_wfs_pop_with_state_blocking(struct cds_wfs_stack *s, int *state)
 {
 	struct cds_wfs_node *retnode;
 
 	_cds_wfs_pop_lock(s);
-	retnode = ___cds_wfs_pop_blocking(s);
+	retnode = ___cds_wfs_pop_with_state_blocking(s, state);
 	_cds_wfs_pop_unlock(s);
 	return retnode;
 }
 
+/*
+ * Call _cds_wfs_pop_with_state_blocking without saving any state.
+ */
+static inline
+struct cds_wfs_node *
+_cds_wfs_pop_blocking(struct cds_wfs_stack *s)
+{
+	return _cds_wfs_pop_with_state_blocking(s, NULL);
+}
+
 /*
  * Call __cds_wfs_pop_all with an internal pop mutex held.
  */