Simplify threadpool refcounting a bit.

Since threadpool shutdown is very strictly controlled,
there is no need to be so precise with reference counts
in queued operations. Since the threadpool shuts down its
own control taskprocessor before doing anything else destructive,
it can be guaranteed that all queued tasks will have a valid
pointer to the pool. This meant that some destructor functions
for helper structs could be removed entirely.



git-svn-id: https://origsvn.digium.com/svn/asterisk/team/mmichelson/threadpool@377210 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/threadpool.c

@@ -161,7 +161,6 @@ struct thread_worker_pair {
 static void thread_worker_pair_destructor(void *obj)
 {
 	struct thread_worker_pair *pair = obj;
-	ao2_ref(pair->pool, -1);
 	ao2_ref(pair->worker, -1);
 }
 
@@ -177,7 +176,6 @@ static struct thread_worker_pair *thread_worker_pair_alloc(struct ast_threadpool
 	if (!pair) {
 		return NULL;
 	}
-	ao2_ref(pool, +1);
 	pair->pool = pool;
 	ao2_ref(worker, +1);
 	pair->worker = worker;
@@ -345,15 +343,6 @@ struct task_pushed_data {
 	int was_empty;
 };
 
-/*!
- * \brief Destructor for task_pushed_data
- */
-static void task_pushed_data_destroy(void *obj)
-{
-	struct task_pushed_data *tpd = obj;
-	ao2_ref(tpd->pool, -1);
-}
-
 /*!
  * \brief Allocate and initialize a task_pushed_data
  * \param pool The threadpool to set in the task_pushed_data
@@ -364,13 +353,11 @@ static void task_pushed_data_destroy(void *obj)
 static struct task_pushed_data *task_pushed_data_alloc(struct ast_threadpool *pool,
 		int was_empty)
 {
-	struct task_pushed_data *tpd = ao2_alloc(sizeof(*tpd),
-			task_pushed_data_destroy);
+	struct task_pushed_data *tpd = ao2_alloc(sizeof(*tpd), NULL);
 
 	if (!tpd) {
 		return NULL;
 	}
-	ao2_ref(pool, +1);
 	tpd->pool = pool;
 	tpd->was_empty = was_empty;
 	return tpd;
@@ -454,7 +441,6 @@ static int handle_emptied(void *data)
 	struct ast_threadpool *pool = data;
 
 	pool->listener->callbacks->emptied(pool->listener);
-	ao2_ref(pool, -1);
 	return 0;
 }
 
@@ -469,7 +455,6 @@ static void threadpool_tps_emptied(struct ast_taskprocessor_listener *listener)
 {
 	struct ast_threadpool *pool = listener->private_data;
 
-	ao2_ref(pool, +1);
 	ast_taskprocessor_push(pool->control_tps, handle_emptied, pool);
 }
 
@@ -636,16 +621,6 @@ struct set_size_data {
 	unsigned int size;
 };
 
-/*!
- * \brief Destructor for set_size_data
- * \param obj The set_size_data to destroy
- */
-static void set_size_data_destroy(void *obj)
-{
-	struct set_size_data *ssd = obj;
-	ao2_ref(ssd->pool, -1);
-}
-
 /*!
  * \brief Allocate and initialize a set_size_data
  * \param pool The pool for the set_size_data
@@ -659,7 +634,6 @@ static struct set_size_data *set_size_data_alloc(struct ast_threadpool *pool,
 		return NULL;
 	}
 
-	ao2_ref(pool, +1);
 	ssd->pool = pool;
 	ssd->size = size;
 	return ssd;