From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 17 Aug 2011 21:54:33 +0000 (-0400)
Subject: CDS API: removal of rcu_read lock/unlock dep, removal of call_rcu argument from init
X-Git-Tag: v0.6.5~48
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=7618919ae496bda84a2efa4f2ad0abe569892a9e;p=urcu.git

CDS API: removal of rcu_read lock/unlock dep, removal of call_rcu argument from init

* API change * for all liburcu-cds* flavors.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/rculfqueue.c b/rculfqueue.c
index 09b8587..c579e75 100644
--- a/rculfqueue.c
+++ b/rculfqueue.c
@@ -44,11 +44,9 @@ void cds_lfq_node_init_rcu(struct cds_lfq_node_rcu *node)
 	_cds_lfq_node_init_rcu(node);
 }
 
-void cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q,
-		      void queue_call_rcu(struct rcu_head *head,
-				void (*func)(struct rcu_head *head)))
+void cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q)
 {
-	_cds_lfq_init_rcu(q, queue_call_rcu);
+	_cds_lfq_init_rcu(q);
 }
 
 int cds_lfq_destroy_rcu(struct cds_lfq_queue_rcu *q)
diff --git a/tests/test_urcu_lfq.c b/tests/test_urcu_lfq.c
index b61a7d4..82a90b0 100644
--- a/tests/test_urcu_lfq.c
+++ b/tests/test_urcu_lfq.c
@@ -180,9 +180,7 @@ void *thr_enqueuer(void *_count)
 		if (!node)
 			goto fail;
 		cds_lfq_node_init_rcu(node);
-		rcu_read_lock();
 		cds_lfq_enqueue_rcu(&q, node);
-		rcu_read_unlock();
 		nr_successful_enqueues++;
 
 		if (unlikely(wdelay))
@@ -230,10 +228,7 @@ void *thr_dequeuer(void *_count)
 	for (;;) {
 		struct cds_lfq_node_rcu *node;
 
-		rcu_read_lock();
 		node = cds_lfq_dequeue_rcu(&q);
-		rcu_read_unlock();
-
 		if (node) {
 			defer_rcu(free, node);
 			nr_successful_dequeues++;
@@ -262,9 +257,7 @@ void test_end(struct cds_lfq_queue_rcu *q, unsigned long long *nr_dequeues)
 	struct cds_lfq_node_rcu *node;
 
 	do {
-		rcu_read_lock();
 		node = cds_lfq_dequeue_rcu(q);
-		rcu_read_unlock();
 		if (node) {
 			free(node);	/* no more concurrent access */
 			(*nr_dequeues)++;
@@ -363,7 +356,7 @@ int main(int argc, char **argv)
 	tid_dequeuer = malloc(sizeof(*tid_dequeuer) * nr_dequeuers);
 	count_enqueuer = malloc(2 * sizeof(*count_enqueuer) * nr_enqueuers);
 	count_dequeuer = malloc(2 * sizeof(*count_dequeuer) * nr_dequeuers);
-	cds_lfq_init_rcu(&q, call_rcu);
+	cds_lfq_init_rcu(&q);
 
 	next_aff = 0;
 
diff --git a/tests/test_urcu_lfs.c b/tests/test_urcu_lfs.c
index 252454d..a7f9af3 100644
--- a/tests/test_urcu_lfs.c
+++ b/tests/test_urcu_lfs.c
@@ -229,9 +229,7 @@ void *thr_dequeuer(void *_count)
 	for (;;) {
 		struct cds_lfs_node_rcu *node;
 
-		rcu_read_lock();
 		node = cds_lfs_pop_rcu(&s);
-		rcu_read_unlock();
 		if (node) {
 			defer_rcu(free, node);
 			nr_successful_dequeues++;
diff --git a/urcu/rculfqueue.h b/urcu/rculfqueue.h
index e1d64f1..1582694 100644
--- a/urcu/rculfqueue.h
+++ b/urcu/rculfqueue.h
@@ -39,8 +39,6 @@ struct cds_lfq_node_rcu {
 
 struct cds_lfq_queue_rcu {
 	struct cds_lfq_node_rcu *head, *tail;
-	void (*queue_call_rcu)(struct rcu_head *head,
-		void (*func)(struct rcu_head *head));
 };
 
 #ifdef _LGPL_SOURCE
@@ -80,9 +78,7 @@ 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,
-			     void queue_call_rcu(struct rcu_head *head,
-					void (*func)(struct rcu_head *head)));
+extern void cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q);
 /*
  * The queue should be emptied before calling destroy.
  *
@@ -91,13 +87,13 @@ extern void cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q,
 extern int cds_lfq_destroy_rcu(struct cds_lfq_queue_rcu *q);
 
 /*
- * Should be called under rcu read lock critical section.
+ * Acts as a RCU reader.
  */
 extern void cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q,
 				struct cds_lfq_node_rcu *node);
 
 /*
- * Should be called under rcu read lock critical section.
+ * Acts as a RCU reader.
  *
  * The caller must wait for a grace period to pass before freeing the returned
  * node or modifying the cds_lfq_node_rcu structure.
diff --git a/urcu/rculfstack.h b/urcu/rculfstack.h
index ad83dbe..f673952 100644
--- a/urcu/rculfstack.h
+++ b/urcu/rculfstack.h
@@ -71,7 +71,7 @@ extern void cds_lfs_init_rcu(struct cds_lfs_stack_rcu *s);
 extern void cds_lfs_push_rcu(struct cds_lfs_stack_rcu *s, struct cds_lfs_node_rcu *node);
 
 /*
- * Should be called under rcu read lock critical section.
+ * Acts as a RCU reader.
  *
  * The caller must wait for a grace period to pass before freeing the returned
  * node or modifying the cds_lfs_node_rcu structure.
diff --git a/urcu/static/rculfqueue.h b/urcu/static/rculfqueue.h
index fea6110..99335c4 100644
--- a/urcu/static/rculfqueue.h
+++ b/urcu/static/rculfqueue.h
@@ -88,7 +88,7 @@ void rcu_free_dummy(struct cds_lfq_node_rcu *node)
 
 	assert(node->dummy);
 	dummy = caa_container_of(node, struct cds_lfq_node_rcu_dummy, parent);
-	dummy->q->queue_call_rcu(&dummy->head, free_dummy_cb);
+	call_rcu(&dummy->head, free_dummy_cb);
 }
 
 static inline
@@ -109,13 +109,10 @@ void _cds_lfq_node_init_rcu(struct cds_lfq_node_rcu *node)
 }
 
 static inline
-void _cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q,
-		       void queue_call_rcu(struct rcu_head *head,
-				void (*func)(struct rcu_head *head)))
+void _cds_lfq_init_rcu(struct cds_lfq_queue_rcu *q)
 {
 	q->tail = make_dummy(q, NULL);
 	q->head = q->tail;
-	q->queue_call_rcu = queue_call_rcu;
 }
 
 /*
@@ -136,7 +133,7 @@ int _cds_lfq_destroy_rcu(struct cds_lfq_queue_rcu *q)
 }
 
 /*
- * Should be called under rcu read lock critical section.
+ * Acts as a RCU reader.
  */
 static inline
 void _cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q,
@@ -150,6 +147,7 @@ void _cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q,
 	for (;;) {
 		struct cds_lfq_node_rcu *tail, *next;
 
+		rcu_read_lock();
 		tail = rcu_dereference(q->tail);
 		next = uatomic_cmpxchg(&tail->next, NULL, node);
 		if (next == NULL) {
@@ -159,6 +157,7 @@ void _cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q,
 			 * enqueue might beat us to it, that's fine).
 			 */
 			(void) uatomic_cmpxchg(&q->tail, tail, node);
+			rcu_read_unlock();
 			return;
 		} else {
 			/*
@@ -166,6 +165,7 @@ void _cds_lfq_enqueue_rcu(struct cds_lfq_queue_rcu *q,
 			 * Help moving tail further and retry.
 			 */
 			(void) uatomic_cmpxchg(&q->tail, tail, next);
+			rcu_read_unlock();
 			continue;
 		}
 	}
@@ -182,7 +182,7 @@ void enqueue_dummy(struct cds_lfq_queue_rcu *q)
 }
 
 /*
- * Should be called under rcu read lock critical section.
+ * Acts as a RCU reader.
  *
  * The caller must wait for a grace period to pass before freeing the returned
  * node or modifying the cds_lfq_node_rcu structure.
@@ -194,10 +194,13 @@ struct cds_lfq_node_rcu *_cds_lfq_dequeue_rcu(struct cds_lfq_queue_rcu *q)
 	for (;;) {
 		struct cds_lfq_node_rcu *head, *next;
 
+		rcu_read_lock();
 		head = rcu_dereference(q->head);
 		next = rcu_dereference(head->next);
-		if (head->dummy && next == NULL)
+		if (head->dummy && next == NULL) {
+			rcu_read_unlock();
 			return NULL;	/* empty */
+		}
 		/*
 		 * We never, ever allow dequeue to get to a state where
 		 * the queue is empty (we need at least one node in the
@@ -209,13 +212,17 @@ struct cds_lfq_node_rcu *_cds_lfq_dequeue_rcu(struct cds_lfq_queue_rcu *q)
 			enqueue_dummy(q);
 			next = rcu_dereference(head->next);
 		}
-		if (uatomic_cmpxchg(&q->head, head, next) != head)
+		if (uatomic_cmpxchg(&q->head, head, next) != head) {
+			rcu_read_unlock();
 			continue;	/* Concurrently pushed. */
+		}
 		if (head->dummy) {
 			/* Free dummy after grace period. */
 			rcu_free_dummy(head);
+			rcu_read_unlock();
 			continue;	/* try again */
 		}
+		rcu_read_unlock();
 		return head;
 	}
 }
diff --git a/urcu/static/rculfstack.h b/urcu/static/rculfstack.h
index ba26231..ed6b0d4 100644
--- a/urcu/static/rculfstack.h
+++ b/urcu/static/rculfstack.h
@@ -63,7 +63,7 @@ void _cds_lfs_push_rcu(struct cds_lfs_stack_rcu *s, struct cds_lfs_node_rcu *nod
 }
 
 /*
- * Should be called under rcu read-side lock.
+ * Acts as a RCU reader.
  *
  * The caller must wait for a grace period to pass before freeing the returned
  * node or modifying the cds_lfs_node_rcu structure.
@@ -76,18 +76,22 @@ _cds_lfs_pop_rcu(struct cds_lfs_stack_rcu *s)
 	for (;;) {
 		struct cds_lfs_node_rcu *head;
 
+		rcu_read_lock();
 		head = rcu_dereference(s->head);
 		if (head) {
 			struct cds_lfs_node_rcu *next = rcu_dereference(head->next);
 
 			if (uatomic_cmpxchg(&s->head, head, next) == head) {
+				rcu_read_unlock();
 				return head;
 			} else {
 				/* Concurrent modification. Retry. */
+				rcu_read_unlock();
 				continue;
 			}
 		} else {
 			/* Empty stack */
+			rcu_read_unlock();
 			return NULL;
 		}
 	}