wfcqueue: return whether dequeue is dequeuing last element

[urcu.git] / urcu / wfcqueue.h

diff --git a/urcu/wfcqueue.h b/urcu/wfcqueue.h
index 4ce8fe962296406b7b69eb75992ea9d910ef6f08..652b42d3ab5da2adda7027f490af4230460a2448 100644 (file)
--- a/urcu/wfcqueue.h
+++ b/urcu/wfcqueue.h
@@ -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;
 };
@@ -85,12 +89,16 @@ 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 +109,8 @@ 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
@@ -199,6 +209,17 @@ 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.
  *
@@ -231,6 +252,17 @@ 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_dequeue_nonblocking: dequeue a node from a wait-free queue.
  *
@@ -241,6 +273,17 @@ extern struct cds_wfcq_node *__cds_wfcq_dequeue_nonblocking(
                struct cds_wfcq_head *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(
+               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.
  *