Create work around for scheduler leaks during shutdown.

* Added ast_sched_clean_by_callback for cleanup of scheduled events
  that have not yet fired.
* Run all pending peercnt_remove_cb and replace_callno events in chan_iax2.
  Cleanup of replace_callno events is only run 11, since it no longer
  releases any references or allocations in 13+.

ASTERISK-24451 #close
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/4425/
........

Merged revisions 431916 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@431917 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_iax2.c

@@ -14692,7 +14692,6 @@ static int __unload_module(void)
 	ao2_ref(users, -1);
 	ao2_ref(iax_peercallno_pvts, -1);
 	ao2_ref(iax_transfercallno_pvts, -1);
-	ao2_ref(peercnts, -1);
 	ao2_ref(callno_limits, -1);
 	ao2_ref(calltoken_ignores, -1);
 	if (timer) {
@@ -14700,8 +14699,11 @@ static int __unload_module(void)
 		timer = NULL;
 	}
 	transmit_processor = ast_taskprocessor_unreference(transmit_processor);
+
+	ast_sched_clean_by_callback(sched, peercnt_remove_cb, peercnt_remove_cb);
 	ast_sched_context_destroy(sched);
 	sched = NULL;
+	ao2_ref(peercnts, -1);
 
 	con = ast_context_find(regcontext);
 	if (con)

include/asterisk/sched.h

@@ -170,6 +170,17 @@ void ast_sched_context_destroy(struct ast_sched_context *c);
 typedef int (*ast_sched_cb)(const void *data);
 #define AST_SCHED_CB(a) ((ast_sched_cb)(a))
 
+/*!
+ * \brief Clean all scheduled events with matching callback.
+ *
+ * \param con Scheduler Context
+ * \param match Callback to match
+ * \param cleanup_cb Callback to run
+ *
+ * \note The return of cleanup_cb is ignored. No events are rescheduled.
+ */
+void ast_sched_clean_by_callback(struct ast_sched_context *con, ast_sched_cb match, ast_sched_cb cleanup_cb);
+
 struct ast_cb_names {
 	int numassocs;
 	char *list[10];

main/sched.c

@@ -289,6 +289,26 @@ static void sched_release(struct ast_sched_context *con, struct sched *tmp)
 		sched_free(tmp);
 }
 
+void ast_sched_clean_by_callback(struct ast_sched_context *con, ast_sched_cb match, ast_sched_cb cleanup_cb)
+{
+	int i = 1;
+	struct sched *current;
+
+	ast_mutex_lock(&con->lock);
+	while ((current = ast_heap_peek(con->sched_heap, i))) {
+		if (current->callback != match) {
+			i++;
+			continue;
+		}
+
+		ast_heap_remove(con->sched_heap, current);
+
+		cleanup_cb(current->data);
+		sched_release(con, current);
+	}
+	ast_mutex_unlock(&con->lock);
+}
+
 /*! \brief
  * Return the number of milliseconds
  * until the next scheduled event