lfqueue: update comments, cleanup

[urcu.git] / urcu / rculfqueue.h

diff --git a/urcu/rculfqueue.h b/urcu/rculfqueue.h
index 7b3f81a50fafc70049c3dc61413a3f61042d332a..fa54ca55a47d4a6b5e5368851abf53fde2b3fb8f 100644 (file)
--- a/urcu/rculfqueue.h
+++ b/urcu/rculfqueue.h
@@ -40,21 +40,26 @@ extern "C" {
  * which point their reference count will be decremented.
  */
 
+struct cds_lfq_queue_rcu;
+
 struct cds_lfq_node_rcu {
        struct cds_lfq_node_rcu *next;
        struct urcu_ref ref;
+       struct cds_lfq_queue_rcu *queue;
+       struct rcu_head rcu_head;
 };
 
 struct cds_lfq_queue_rcu {
        struct cds_lfq_node_rcu *head, *tail;
        struct cds_lfq_node_rcu init;   /* Dummy initialization node */
+       void (*release)(struct urcu_ref *ref);
 };
 
 #ifdef _LGPL_SOURCE
 
 #include <urcu/rculfqueue-static.h>
 
-#define cds_lfq_node_init_rcu  _cds_lfq_node_init_rcu
+#define cds_lfq_node_init_rcu          _cds_lfq_node_init_rcu
 #define cds_lfq_init_rcu               _cds_lfq_init_rcu
 #define cds_lfq_enqueue_rcu            _cds_lfq_enqueue_rcu
 #define cds_lfq_dequeue_rcu            _cds_lfq_dequeue_rcu
@@ -62,21 +67,27 @@ struct cds_lfq_queue_rcu {
 #else /* !_LGPL_SOURCE */
 
 extern void cds_lfq_node_init_rcu(struct cds_lfq_node_rcu *node);
-extern void cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q);
-extern void cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q, struct cds_lfq_node_rcu *node);
+extern void cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q,
+                            void (*release)(struct urcu_ref *ref));
+
+/*
+ * Should be called under rcu read lock critical section.
+ */
+extern void cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q,
+                               struct cds_lfq_node_rcu *node);
 
 /*
- * The entry returned by dequeue must be taken care of by doing a urcu_ref_put,
- * which calls the release primitive when the reference count drops to zero. A
- * grace period must be waited after execution of the release callback before
- * performing the actual memory reclamation or modifying the cds_lfq_node_rcu
- * structure.
+ * Should be called under rcu read lock critical section.
+ *
+ * The entry returned by dequeue must be taken care of by doing a
+ * sequence of urcu_ref_put which release handler should do a call_rcu.
+ *
  * In other words, the entry lfq node returned by dequeue must not be
  * modified/re-used/freed until the reference count reaches zero and a grace
  * period has elapsed (after the refcount reached 0).
  */
-extern struct cds_lfq_node_rcu *
-cds_lfq_dequeue_rcu(struct cds_lfq_queue_rcu *q, void (*release)(struct urcu_ref *));
+extern
+struct cds_lfq_node_rcu *cds_lfq_dequeue_rcu(struct cds_lfq_queue_rcu *q);
 
 #endif /* !_LGPL_SOURCE */