Fix: handle sys_futex() FUTEX_WAIT interrupted by signal

[urcu.git] / urcu / wfqueue.h

diff --git a/urcu/wfqueue.h b/urcu/wfqueue.h
index b4208dae65f28e0f0564c07dd77f338f72b4862b..4cd4b135860c2c59ac5c88bfe9298eaff3a1adfe 100644 (file)
--- a/urcu/wfqueue.h
+++ b/urcu/wfqueue.h
@@ -31,8 +31,9 @@
 extern "C" {
 #endif
 
-#if (!defined(_GNU_SOURCE) && !defined(_LGPL_SOURCE))
-#error "Dynamic loader LGPL wrappers not implemented yet"
+#ifndef CDS_WFQ_DEPRECATED
+#define CDS_WFQ_DEPRECATED     \
+       CDS_DEPRECATED("urcu/wfqueue.h is deprecated. Please use urcu/wfcqueue.h instead.")
 #endif
 
 /*
@@ -44,111 +45,70 @@ extern "C" {
  * Paul E. McKenney.
  */
 
-struct wfq_node {
-       struct wfq_node *next;
+struct cds_wfq_node {
+       struct cds_wfq_node *next;
 };
 
-struct wfq_queue {
-       struct wfq_node *head, **tail;
-       struct wfq_node dummy;  /* Dummy node */
+struct cds_wfq_queue {
+       struct cds_wfq_node *head, **tail;
+       struct cds_wfq_node dummy;      /* Dummy node */
        pthread_mutex_t lock;
 };
 
-void wfq_node_init(struct wfq_node *node)
+#ifdef _LGPL_SOURCE
+
+#include <urcu/static/wfqueue.h>
+
+static inline CDS_WFQ_DEPRECATED
+void cds_wfq_node_init(struct cds_wfq_node *node)
 {
-       node->next = NULL;
+       _cds_wfq_node_init(node);
 }
 
-void wfq_init(struct wfq_queue *q)
+static inline CDS_WFQ_DEPRECATED
+void cds_wfq_init(struct cds_wfq_queue *q)
 {
-       int ret;
-
-       wfq_node_init(&q->dummy);
-       /* Set queue head and tail */
-       q->head = &q->dummy;
-       q->tail = &q->dummy.next;
-       ret = pthread_mutex_init(&q->lock, NULL);
-       assert(!ret);
+       _cds_wfq_init(q);
 }
 
-void wfq_enqueue(struct wfq_queue *q, struct wfq_node *node)
+static inline CDS_WFQ_DEPRECATED
+void cds_wfq_enqueue(struct cds_wfq_queue *q, struct cds_wfq_node *node)
 {
-       struct wfq_node **old_tail;
-
-       /*
-        * uatomic_xchg() implicit memory barrier orders earlier stores to data
-        * structure containing node and setting node->next to NULL before
-        * publication.
-        */
-       old_tail = uatomic_xchg(&q->tail, node);
-       /*
-        * At this point, dequeuers see a NULL old_tail->next, which indicates
-        * that the queue is being appended to. The following store will append
-        * "node" to the queue from a dequeuer perspective.
-        */
-       STORE_SHARED(*old_tail, node);
+       _cds_wfq_enqueue(q, node);
 }
 
-/*
- * It is valid to reuse and free a dequeued node immediately.
- *
- * No need to go on a waitqueue here, as there is no possible state in which the
- * list could cause dequeue to busy-loop needlessly while waiting for another
- * thread to be scheduled. The queue appears empty until tail->next is set by
- * enqueue.
- */
-struct wfq_node *
-__wfq_dequeue_blocking(struct wfq_queue *q)
+static inline CDS_WFQ_DEPRECATED
+struct cds_wfq_node *__cds_wfq_dequeue_blocking(struct cds_wfq_queue *q)
 {
-       struct wfq_node *node, *next;
-       int busy_wait = 16;
-
-       /*
-        * Queue is empty if it only contains the dummy node.
-        */
-       if (q->head == &q->dummy && LOAD_SHARED(q->tail) == &q->dummy.next)
-               return NULL;
-       node = q->head;
-
-       /*
-        * Adaptative busy-looping waiting for enqueuer to complete enqueue.
-        */
-       while ((next = LOAD_SHARED(node->next)) == NULL) {
-               if (busy_wait > 0) {
-                       cpu_relax();
-                       busy_wait--;
-               } else
-                       poll(NULL, 0, 1);       /* Wait for 1ms */
-       }
-       /*
-        * Move queue head forward.
-        */
-       q->head = next;
-       /*
-        * Requeue dummy node if we just dequeued it.
-        */
-       if (node == &q->dummy) {
-               wfq_node_init(node);
-               wfq_enqueue(q, node);
-               return __wfq_dequeue_blocking(q);
-       }
-       return node;
+       return ___cds_wfq_dequeue_blocking(q);
 }
 
-struct wfq_node *
-wfq_dequeue_blocking(struct wfq_queue *q)
+static inline CDS_WFQ_DEPRECATED
+struct cds_wfq_node *cds_wfq_dequeue_blocking(struct cds_wfq_queue *q)
 {
-       struct wfq_node *retnode;
-       int ret;
-
-       ret = pthread_mutex_lock(&q->lock);
-       assert(!ret);
-       retnode = __wfq_dequeue_blocking(q);
-       ret = pthread_mutex_unlock(&q->lock);
-       assert(!ret);
-       return retnode;
+       return _cds_wfq_dequeue_blocking(q);
 }
 
+#else /* !_LGPL_SOURCE */
+
+extern CDS_WFQ_DEPRECATED
+void cds_wfq_node_init(struct cds_wfq_node *node);
+
+extern CDS_WFQ_DEPRECATED
+void cds_wfq_init(struct cds_wfq_queue *q);
+
+extern CDS_WFQ_DEPRECATED
+void cds_wfq_enqueue(struct cds_wfq_queue *q, struct cds_wfq_node *node);
+
+/* __cds_wfq_dequeue_blocking: caller ensures mutual exclusion between dequeues */
+extern CDS_WFQ_DEPRECATED
+struct cds_wfq_node *__cds_wfq_dequeue_blocking(struct cds_wfq_queue *q);
+
+extern CDS_WFQ_DEPRECATED
+struct cds_wfq_node *cds_wfq_dequeue_blocking(struct cds_wfq_queue *q);
+
+#endif /* !_LGPL_SOURCE */
+
 #ifdef __cplusplus
 }
 #endif