X-Git-Url: https://git.lttng.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Fwfstack.h;h=fc0b44b791fcf218c56714711e235cc40465296f;hp=aa10881506a5ad2609cb62a39b18ee916e1676d2;hb=92af1a30ca6a70945b167c31631c8598a626c71a;hpb=a03a0f42bd1e3ca7c0cb207d9d5b19c61e696068

diff --git a/urcu/wfstack.h b/urcu/wfstack.h
index aa10881..fc0b44b 100644
--- a/urcu/wfstack.h
+++ b/urcu/wfstack.h
@@ -38,9 +38,10 @@ extern "C" {
  * Stack implementing push, pop, pop_all operations, as well as iterator
  * on the stack head returned by pop_all.
  *
- * Wait-free operations: cds_wfs_push, __cds_wfs_pop_all.
- * Blocking operations: cds_wfs_pop, cds_wfs_pop_all, iteration on stack
- *                      head returned by pop_all.
+ * Wait-free operations: cds_wfs_push, __cds_wfs_pop_all, cds_wfs_empty,
+ *                       cds_wfs_first.
+ * Blocking operations: cds_wfs_pop, cds_wfs_pop_all, cds_wfs_next,
+ *                      iteration on stack head returned by pop_all.
  *
  * Synchronization table:
  *
@@ -57,6 +58,12 @@ extern "C" {
  * synchronization.
  */
 
+#define CDS_WFS_WOULDBLOCK	((void *) -1UL)
+
+enum cds_wfs_state {
+	CDS_WFS_STATE_LAST =		(1U << 0),
+};
+
 /*
  * struct cds_wfs_node is returned by __cds_wfs_pop, and also used as
  * iterator on stack. It is not safe to dereference the node next
@@ -92,14 +99,16 @@ struct cds_wfs_stack {
 
 /* Locking performed internally */
 #define cds_wfs_pop_blocking		_cds_wfs_pop_blocking
+#define cds_wfs_pop_with_state_blocking	_cds_wfs_pop_with_state_blocking
 #define cds_wfs_pop_all_blocking	_cds_wfs_pop_all_blocking
 
 /*
  * For iteration on cds_wfs_head returned by __cds_wfs_pop_all or
  * cds_wfs_pop_all_blocking.
  */
-#define cds_wfs_first_blocking		_cds_wfs_first_blocking
+#define cds_wfs_first			_cds_wfs_first
 #define cds_wfs_next_blocking		_cds_wfs_next_blocking
+#define cds_wfs_next_nonblocking	_cds_wfs_next_nonblocking
 
 /* Pop locking with internal mutex */
 #define cds_wfs_pop_lock		_cds_wfs_pop_lock
@@ -107,6 +116,11 @@ struct cds_wfs_stack {
 
 /* Synchronization ensured by the caller. See synchronization table. */
 #define __cds_wfs_pop_blocking		___cds_wfs_pop_blocking
+#define __cds_wfs_pop_with_state_blocking	\
+					___cds_wfs_pop_with_state_blocking
+#define __cds_wfs_pop_nonblocking	___cds_wfs_pop_nonblocking
+#define __cds_wfs_pop_with_state_nonblocking	\
+					___cds_wfs_pop_with_state_nonblocking
 #define __cds_wfs_pop_all		___cds_wfs_pop_all
 
 #else /* !_LGPL_SOURCE */
@@ -146,6 +160,15 @@ extern int cds_wfs_push(struct cds_wfs_stack *s, struct cds_wfs_node *node);
  */
 extern struct cds_wfs_node *cds_wfs_pop_blocking(struct cds_wfs_stack *s);
 
+/*
+ * cds_wfs_pop_with_state_blocking: pop a node from the stack, with state.
+ *
+ * Same as cds_wfs_pop_blocking, but stores whether the stack was
+ * empty into state (CDS_WFS_STATE_LAST).
+ */
+extern struct cds_wfs_node *
+	cds_wfs_pop_with_state_blocking(struct cds_wfs_stack *s, int *state);
+
 /*
  * cds_wfs_pop_all_blocking: pop all nodes from a stack.
  *
@@ -154,7 +177,7 @@ extern struct cds_wfs_node *cds_wfs_pop_blocking(struct cds_wfs_stack *s);
 extern struct cds_wfs_head *cds_wfs_pop_all_blocking(struct cds_wfs_stack *s);
 
 /*
- * cds_wfs_first_blocking: get first node of a popped stack.
+ * cds_wfs_first: get first node of a popped stack.
  *
  * Content written into the node before enqueue is guaranteed to be
  * consistent, but no other memory ordering is ensured.
@@ -162,8 +185,10 @@ extern struct cds_wfs_head *cds_wfs_pop_all_blocking(struct cds_wfs_stack *s);
  * Used by for-like iteration macros in urcu/wfstack.h:
  * cds_wfs_for_each_blocking()
  * cds_wfs_for_each_blocking_safe()
+ *
+ * Returns NULL if popped stack is empty, top stack node otherwise.
  */
-extern struct cds_wfs_node *cds_wfs_first_blocking(struct cds_wfs_head *head);
+extern struct cds_wfs_node *cds_wfs_first(struct cds_wfs_head *head);
 
 /*
  * cds_wfs_next_blocking: get next node of a popped stack.
@@ -174,9 +199,20 @@ extern struct cds_wfs_node *cds_wfs_first_blocking(struct cds_wfs_head *head);
  * Used by for-like iteration macros in urcu/wfstack.h:
  * cds_wfs_for_each_blocking()
  * cds_wfs_for_each_blocking_safe()
+ *
+ * Returns NULL if reached end of popped stack, non-NULL next stack
+ * node otherwise.
  */
 extern struct cds_wfs_node *cds_wfs_next_blocking(struct cds_wfs_node *node);
 
+/*
+ * cds_wfs_next_nonblocking: get next node of a popped stack.
+ *
+ * Same as cds_wfs_next_blocking, but returns CDS_WFS_WOULDBLOCK if it
+ * needs to block.
+ */
+extern struct cds_wfs_node *cds_wfs_next_nonblocking(struct cds_wfs_node *node);
+
 /*
  * cds_wfs_pop_lock: lock stack pop-protection mutex.
  */
@@ -205,6 +241,33 @@ extern void cds_wfs_pop_unlock(struct cds_wfs_stack *s);
  */
 extern struct cds_wfs_node *__cds_wfs_pop_blocking(struct cds_wfs_stack *s);
 
+/*
+ * __cds_wfs_pop_with_state_blocking: pop a node from the stack, with state.
+ *
+ * Same as __cds_wfs_pop_blocking, but stores whether the stack was
+ * empty into state (CDS_WFS_STATE_LAST).
+ */
+extern struct cds_wfs_node *
+	__cds_wfs_pop_with_state_blocking(struct cds_wfs_stack *s, int *state);
+
+/*
+ * __cds_wfs_pop_nonblocking: pop a node from the stack.
+ *
+ * Same as __cds_wfs_pop_blocking, but returns CDS_WFS_WOULDBLOCK if
+ * it needs to block.
+ */
+extern struct cds_wfs_node *__cds_wfs_pop_nonblocking(struct cds_wfs_stack *s);
+
+/*
+ * __cds_wfs_pop_with_state_nonblocking: pop a node from the stack, with state.
+ *
+ * Same as __cds_wfs_pop_nonblocking, but stores whether the stack was
+ * empty into state (CDS_WFS_STATE_LAST).
+ */
+extern struct cds_wfs_node *
+	__cds_wfs_pop_with_state_nonblocking(struct cds_wfs_stack *s,
+		int *state);
+
 /*
  * __cds_wfs_pop_all: pop all nodes from a stack.
  *
@@ -240,7 +303,7 @@ extern struct cds_wfs_head *__cds_wfs_pop_all(struct cds_wfs_stack *s);
  * consistent, but no other memory ordering is ensured.
  */
 #define cds_wfs_for_each_blocking(head, node)			\
-	for (node = cds_wfs_first_blocking(head);		\
+	for (node = cds_wfs_first(head);			\
 		node != NULL;					\
 		node = cds_wfs_next_blocking(node))
 
@@ -256,7 +319,7 @@ extern struct cds_wfs_head *__cds_wfs_pop_all(struct cds_wfs_stack *s);
  * consistent, but no other memory ordering is ensured.
  */
 #define cds_wfs_for_each_blocking_safe(head, node, n)			   \
-	for (node = cds_wfs_first_blocking(head),			   \
+	for (node = cds_wfs_first(head),				   \
 			n = (node ? cds_wfs_next_blocking(node) : NULL);   \
 		node != NULL;						   \
 		node = n, n = (node ? cds_wfs_next_blocking(node) : NULL))