From 23783a9164b525b4c134ec6ede8c6159d9b7eb50 Mon Sep 17 00:00:00 2001
From: Howard Chu <hyc@openldap.org>
Date: Thu, 11 Jun 2009 04:46:04 +0000
Subject: [PATCH] Add ldap_pvt_thread_pool_retract() to cancel pending threads

---
 include/ldap_pvt_thread.h   |  6 ++++++
 libraries/libldap_r/tpool.c | 34 ++++++++++++++++++++++++++++++++++
 servers/slapd/syncrepl.c    | 20 ++++++--------------
 3 files changed, 46 insertions(+), 14 deletions(-)

diff --git a/include/ldap_pvt_thread.h b/include/ldap_pvt_thread.h
index 738140fb2f..bd928a771f 100644
--- a/include/ldap_pvt_thread.h
+++ b/include/ldap_pvt_thread.h
@@ -215,6 +215,12 @@ ldap_pvt_thread_pool_submit LDAP_P((
 	ldap_pvt_thread_start_t *start,
 	void *arg ));
 
+LDAP_F( int )
+ldap_pvt_thread_pool_retract LDAP_P((
+	ldap_pvt_thread_pool_t *pool,
+	ldap_pvt_thread_start_t *start,
+	void *arg ));
+
 LDAP_F( int )
 ldap_pvt_thread_pool_maxthreads LDAP_P((
 	ldap_pvt_thread_pool_t *pool,
diff --git a/libraries/libldap_r/tpool.c b/libraries/libldap_r/tpool.c
index 209a1ac800..7e841898f5 100644
--- a/libraries/libldap_r/tpool.c
+++ b/libraries/libldap_r/tpool.c
@@ -373,6 +373,40 @@ ldap_pvt_thread_pool_submit (
 	return(-1);
 }
 
+/* Cancel a pending thread that was previously submitted.
+ * Return 1 if the thread was successfully cancelled, 0 if
+ * not found, -1 for invalid parameters
+ */
+int
+ldap_pvt_thread_pool_retract (
+	ldap_pvt_thread_pool_t *tpool,
+	ldap_pvt_thread_start_t *start_routine, void *arg )
+{
+	struct ldap_int_thread_pool_s *pool;
+	ldap_int_thread_task_t *task;
+
+	if (tpool == NULL)
+		return(-1);
+
+	pool = *tpool;
+
+	if (pool == NULL)
+		return(-1);
+
+	ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+	LDAP_STAILQ_FOREACH(task, &pool->ltp_pending_list, ltt_next.q)
+		if (task->ltt_start_routine == start_routine &&
+			task->ltt_arg == arg) {
+			pool->ltp_pending_count--;
+			LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, task,
+				ldap_int_thread_task_s, ltt_next.q);
+			LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, task,
+				ltt_next.l);
+			return 1;
+		}
+	return 0;
+}
+
 /* Set max #threads.  value <= 0 means max supported #threads (LDAP_MAXTHR) */
 int
 ldap_pvt_thread_pool_maxthreads(
diff --git a/servers/slapd/syncrepl.c b/servers/slapd/syncrepl.c
index 6b16e0470f..07e9dd7857 100644
--- a/servers/slapd/syncrepl.c
+++ b/servers/slapd/syncrepl.c
@@ -4631,21 +4631,13 @@ syncrepl_config( ConfigArgs *c )
 							isrunning = 1;
 						} else {
 							if ( si->si_conn ) {
-								isrunning = 1;
-								/* If there's a persistent connection, we don't
-								 * know if it's already got a thread queued.
-								 * so defer the free, but reschedule the task.
-								 * If there's a connection thread queued, it
-								 * will cleanup as necessary. If not, then the
-								 * runqueue task will cleanup.
+								/* If there's a persistent connection, it may
+								 * already have a thread queued. We know it's
+								 * not active, so it must be pending and we
+								 * can simply cancel it now.
 								 */
-								ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
-								if ( !ldap_pvt_runqueue_isrunning( &slapd_rq, si->si_re )) {
-									si->si_re->interval.tv_sec = 0;
-									ldap_pvt_runqueue_resched( &slapd_rq, si->si_re, 0 );
-									si->si_re->interval.tv_sec = si->si_interval;
-								}
-								ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
+								ldap_pvt_thread_pool_retract( &connection_pool,
+									si->si_re->routine, si->si_re );
 							}
 							ldap_pvt_thread_mutex_unlock( &si->si_mutex );
 						}
-- 
2.39.5