X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Fwfcqueue.h;h=6c6ebba9e4453257da70484cecc6840bbdab0364;hp=d9ec5349d7be203da7f80f6e6c0de5cda96e20e9;hb=200d100e05ed8e10c47f971939042f2406df92ef;hpb=f878b49ebb78010f4f9466d3512a7e88787812b2

diff --git a/urcu/wfcqueue.h b/urcu/wfcqueue.h
index d9ec534..6c6ebba 100644
--- a/urcu/wfcqueue.h
+++ b/urcu/wfcqueue.h
@@ -43,7 +43,7 @@ extern "C" {
  * McKenney.
  */
 
-#define CDS_WFCQ_WOULDBLOCK	((void *) -1UL)
+#define CDS_WFCQ_WOULDBLOCK	((struct cds_wfcq_node *) -1UL)
 
 enum cds_wfcq_ret {
 	CDS_WFCQ_RET_WOULDBLOCK =	-1,
@@ -52,6 +52,10 @@ enum cds_wfcq_ret {
 	CDS_WFCQ_RET_SRC_EMPTY = 	2,
 };
 
+enum cds_wfcq_state {
+	CDS_WFCQ_STATE_LAST =		(1U << 0),
+};
+
 struct cds_wfcq_node {
 	struct cds_wfcq_node *next;
 };
@@ -61,11 +65,65 @@ struct cds_wfcq_node {
  * enqueue/dequeue are expected from many CPUs. This eliminates
  * false-sharing between enqueue and dequeue.
  */
+struct __cds_wfcq_head {
+	struct cds_wfcq_node node;
+};
+
 struct cds_wfcq_head {
 	struct cds_wfcq_node node;
 	pthread_mutex_t lock;
 };
 
+#ifndef __cplusplus
+/*
+ * The transparent union allows calling functions that work on both
+ * struct cds_wfcq_head and struct __cds_wfcq_head on any of those two
+ * types.
+ */
+typedef union {
+	struct __cds_wfcq_head *_h;
+	struct cds_wfcq_head *h;
+} __attribute__((__transparent_union__)) cds_wfcq_head_ptr_t;
+
+/*
+ * This static inline is only present for compatibility with C++. It is
+ * effect-less in C.
+ */
+static inline struct __cds_wfcq_head *__cds_wfcq_head_cast(struct __cds_wfcq_head *head)
+{
+	return head;
+}
+
+/*
+ * This static inline is only present for compatibility with C++. It is
+ * effect-less in C.
+ */
+static inline struct cds_wfcq_head *cds_wfcq_head_cast(struct cds_wfcq_head *head)
+{
+	return head;
+}
+#else /* #ifndef __cplusplus */
+
+/* C++ ignores transparent union. */
+typedef union {
+	struct __cds_wfcq_head *_h;
+	struct cds_wfcq_head *h;
+} cds_wfcq_head_ptr_t;
+
+/* C++ ignores transparent union. Requires an explicit conversion. */
+static inline cds_wfcq_head_ptr_t __cds_wfcq_head_cast(struct __cds_wfcq_head *head)
+{
+	cds_wfcq_head_ptr_t ret = { ._h = head };
+	return ret;
+}
+/* C++ ignores transparent union. Requires an explicit conversion. */
+static inline cds_wfcq_head_ptr_t cds_wfcq_head_cast(struct cds_wfcq_head *head)
+{
+	cds_wfcq_head_ptr_t ret = { .h = head };
+	return ret;
+}
+#endif /* #else #ifndef __cplusplus */
+
 struct cds_wfcq_tail {
 	struct cds_wfcq_node *p;
 };
@@ -76,6 +134,8 @@ struct cds_wfcq_tail {
 
 #define cds_wfcq_node_init		_cds_wfcq_node_init
 #define cds_wfcq_init			_cds_wfcq_init
+#define __cds_wfcq_init			___cds_wfcq_init
+#define cds_wfcq_destroy		_cds_wfcq_destroy
 #define cds_wfcq_empty			_cds_wfcq_empty
 #define cds_wfcq_enqueue		_cds_wfcq_enqueue
 
@@ -85,12 +145,16 @@ struct cds_wfcq_tail {
 
 /* Locking performed within cds_wfcq calls. */
 #define cds_wfcq_dequeue_blocking	_cds_wfcq_dequeue_blocking
+#define cds_wfcq_dequeue_with_state_blocking	\
+					_cds_wfcq_dequeue_with_state_blocking
 #define cds_wfcq_splice_blocking	_cds_wfcq_splice_blocking
 #define cds_wfcq_first_blocking		_cds_wfcq_first_blocking
 #define cds_wfcq_next_blocking		_cds_wfcq_next_blocking
 
 /* Locking ensured by caller by holding cds_wfcq_dequeue_lock() */
 #define __cds_wfcq_dequeue_blocking	___cds_wfcq_dequeue_blocking
+#define __cds_wfcq_dequeue_with_state_blocking	\
+					___cds_wfcq_dequeue_with_state_blocking
 #define __cds_wfcq_splice_blocking	___cds_wfcq_splice_blocking
 #define __cds_wfcq_first_blocking	___cds_wfcq_first_blocking
 #define __cds_wfcq_next_blocking	___cds_wfcq_next_blocking
@@ -101,6 +165,8 @@ struct cds_wfcq_tail {
  * need to block. splice returns nonzero if it needs to block.
  */
 #define __cds_wfcq_dequeue_nonblocking	___cds_wfcq_dequeue_nonblocking
+#define __cds_wfcq_dequeue_with_state_nonblocking	\
+				___cds_wfcq_dequeue_with_state_nonblocking
 #define __cds_wfcq_splice_nonblocking	___cds_wfcq_splice_nonblocking
 #define __cds_wfcq_first_nonblocking	___cds_wfcq_first_nonblocking
 #define __cds_wfcq_next_nonblocking	___cds_wfcq_next_nonblocking
@@ -148,17 +214,32 @@ struct cds_wfcq_tail {
 extern void cds_wfcq_node_init(struct cds_wfcq_node *node);
 
 /*
- * cds_wfcq_init: initialize wait-free queue.
+ * cds_wfcq_init: initialize wait-free queue. Pair with
+ * cds_wfcq_destroy().
  */
 extern void cds_wfcq_init(struct cds_wfcq_head *head,
 		struct cds_wfcq_tail *tail);
 
+/*
+ * cds_wfcq_destroy: destroy wait-free queue. Pair with
+ * cds_wfcq_init().
+ */
+extern void cds_wfcq_destroy(struct cds_wfcq_head *head,
+		struct cds_wfcq_tail *tail);
+
+/*
+ * __cds_wfcq_init: initialize wait-free queue (without lock). Don't
+ * pair with any destroy function.
+ */
+extern void __cds_wfcq_init(struct __cds_wfcq_head *head,
+		struct cds_wfcq_tail *tail);
+
 /*
  * cds_wfcq_empty: return whether wait-free queue is empty.
  *
  * No memory barrier is issued. No mutual exclusion is required.
  */
-extern bool cds_wfcq_empty(struct cds_wfcq_head *head,
+extern bool cds_wfcq_empty(cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail);
 
 /*
@@ -182,7 +263,7 @@ extern void cds_wfcq_dequeue_unlock(struct cds_wfcq_head *head,
  * Returns false if the queue was empty prior to adding the node.
  * Returns true otherwise.
  */
-extern bool cds_wfcq_enqueue(struct cds_wfcq_head *head,
+extern bool cds_wfcq_enqueue(cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail,
 		struct cds_wfcq_node *node);
 
@@ -192,13 +273,24 @@ extern bool cds_wfcq_enqueue(struct cds_wfcq_head *head,
  * Content written into the node before enqueue is guaranteed to be
  * consistent, but no other memory ordering is ensured.
  * It is valid to reuse and free a dequeued node immediately.
- * Mutual exlusion with cds_wfcq_dequeue_blocking and dequeue lock is
+ * Mutual exclusion with cds_wfcq_dequeue_blocking and dequeue lock is
  * ensured.
  */
 extern struct cds_wfcq_node *cds_wfcq_dequeue_blocking(
 		struct cds_wfcq_head *head,
 		struct cds_wfcq_tail *tail);
 
+/*
+ * cds_wfcq_dequeue_with_state_blocking: dequeue with state.
+ *
+ * Same as cds_wfcq_dequeue_blocking, but saves whether dequeueing the
+ * last node of the queue into state (CDS_WFCQ_STATE_LAST).
+ */
+extern struct cds_wfcq_node *cds_wfcq_dequeue_with_state_blocking(
+		struct cds_wfcq_head *head,
+		struct cds_wfcq_tail *tail,
+		int *state);
+
 /*
  * cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q.
  *
@@ -206,11 +298,11 @@ extern struct cds_wfcq_node *cds_wfcq_dequeue_blocking(
  * dest_q must be already initialized.
  * Content written into the node before enqueue is guaranteed to be
  * consistent, but no other memory ordering is ensured.
- * Mutual exlusion with cds_wfcq_dequeue_blocking and dequeue lock is
+ * Mutual exclusion with cds_wfcq_dequeue_blocking and dequeue lock is
  * ensured.
  *
  * Returns enum cds_wfcq_ret which indicates the state of the src or
- * dest queue. Cannot block.
+ * dest queue.
  */
 extern enum cds_wfcq_ret cds_wfcq_splice_blocking(
 		struct cds_wfcq_head *dest_q_head,
@@ -228,9 +320,20 @@ extern enum cds_wfcq_ret cds_wfcq_splice_blocking(
  * caller.
  */
 extern struct cds_wfcq_node *__cds_wfcq_dequeue_blocking(
-		struct cds_wfcq_head *head,
+		cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail);
 
+/*
+ * __cds_wfcq_dequeue_with_state_blocking: dequeue with state.
+ *
+ * Same as __cds_wfcq_dequeue_blocking, but saves whether dequeueing the
+ * last node of the queue into state (CDS_WFCQ_STATE_LAST).
+ */
+extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_blocking(
+		cds_wfcq_head_ptr_t head,
+		struct cds_wfcq_tail *tail,
+		int *state);
+
 /*
  * __cds_wfcq_dequeue_nonblocking: dequeue a node from a wait-free queue.
  *
@@ -238,9 +341,20 @@ extern struct cds_wfcq_node *__cds_wfcq_dequeue_blocking(
  * if it needs to block.
  */
 extern struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking(
-		struct cds_wfcq_head *head,
+		cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail);
 
+/*
+ * __cds_wfcq_dequeue_with_state_blocking: dequeue with state.
+ *
+ * Same as __cds_wfcq_dequeue_nonblocking, but saves whether dequeueing
+ * the last node of the queue into state (CDS_WFCQ_STATE_LAST).
+ */
+extern struct cds_wfcq_node *__cds_wfcq_dequeue_with_state_nonblocking(
+		cds_wfcq_head_ptr_t head,
+		struct cds_wfcq_tail *tail,
+		int *state);
+
 /*
  * __cds_wfcq_splice_blocking: enqueue all src_q nodes at the end of dest_q.
  *
@@ -252,9 +366,9 @@ extern struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking(
  * dest queue. Never returns CDS_WFCQ_RET_WOULDBLOCK.
  */
 extern enum cds_wfcq_ret __cds_wfcq_splice_blocking(
-		struct cds_wfcq_head *dest_q_head,
+		cds_wfcq_head_ptr_t dest_q_head,
 		struct cds_wfcq_tail *dest_q_tail,
-		struct cds_wfcq_head *src_q_head,
+		cds_wfcq_head_ptr_t src_q_head,
 		struct cds_wfcq_tail *src_q_tail);
 
 /*
@@ -264,9 +378,9 @@ extern enum cds_wfcq_ret __cds_wfcq_splice_blocking(
  * CDS_WFCQ_RET_WOULDBLOCK if it needs to block.
  */
 extern enum cds_wfcq_ret __cds_wfcq_splice_nonblocking(
-		struct cds_wfcq_head *dest_q_head,
+		cds_wfcq_head_ptr_t dest_q_head,
 		struct cds_wfcq_tail *dest_q_tail,
-		struct cds_wfcq_head *src_q_head,
+		cds_wfcq_head_ptr_t src_q_head,
 		struct cds_wfcq_tail *src_q_tail);
 
 /*
@@ -280,9 +394,11 @@ extern enum cds_wfcq_ret __cds_wfcq_splice_nonblocking(
  * Used by for-like iteration macros:
  * __cds_wfcq_for_each_blocking()
  * __cds_wfcq_for_each_blocking_safe()
+ *
+ * Returns NULL if queue is empty, first node otherwise.
  */
 extern struct cds_wfcq_node *__cds_wfcq_first_blocking(
-		struct cds_wfcq_head *head,
+		cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail);
 
 /*
@@ -292,7 +408,7 @@ extern struct cds_wfcq_node *__cds_wfcq_first_blocking(
  * it needs to block.
  */
 extern struct cds_wfcq_node *__cds_wfcq_first_nonblocking(
-		struct cds_wfcq_head *head,
+		cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail);
 
 /*
@@ -306,9 +422,12 @@ extern struct cds_wfcq_node *__cds_wfcq_first_nonblocking(
  * Used by for-like iteration macros:
  * __cds_wfcq_for_each_blocking()
  * __cds_wfcq_for_each_blocking_safe()
+ *
+ * Returns NULL if reached end of queue, non-NULL next queue node
+ * otherwise.
  */
 extern struct cds_wfcq_node *__cds_wfcq_next_blocking(
-		struct cds_wfcq_head *head,
+		cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail,
 		struct cds_wfcq_node *node);
 
@@ -319,7 +438,7 @@ extern struct cds_wfcq_node *__cds_wfcq_next_blocking(
  * it needs to block.
  */
 extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking(
-		struct cds_wfcq_head *head,
+		cds_wfcq_head_ptr_t head,
 		struct cds_wfcq_tail *tail,
 		struct cds_wfcq_node *node);
 
@@ -328,7 +447,7 @@ extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking(
 /*
  * __cds_wfcq_for_each_blocking: Iterate over all nodes in a queue,
  * without dequeuing them.
- * @head: head of the queue (struct cds_wfcq_head pointer).
+ * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer).
  * @tail: tail of the queue (struct cds_wfcq_tail pointer).
  * @node: iterator on the queue (struct cds_wfcq_node pointer).
  *
@@ -345,7 +464,7 @@ extern struct cds_wfcq_node *__cds_wfcq_next_nonblocking(
 /*
  * __cds_wfcq_for_each_blocking_safe: Iterate over all nodes in a queue,
  * without dequeuing them. Safe against deletion.
- * @head: head of the queue (struct cds_wfcq_head pointer).
+ * @head: head of the queue (struct cds_wfcq_head or __cds_wfcq_head pointer).
  * @tail: tail of the queue (struct cds_wfcq_tail pointer).
  * @node: iterator on the queue (struct cds_wfcq_node pointer).
  * @n: struct cds_wfcq_node pointer holding the next pointer (used