diff --git a/src/factory/WFTask.inl b/src/factory/WFTask.inl
index f06fdfea2a..d62a5ba439 100644
--- a/src/factory/WFTask.inl
+++ b/src/factory/WFTask.inl
@@ -47,7 +47,7 @@ class WFClientTask : public WFNetworkTask<REQ, RESP>
 protected:
 	virtual CommMessageOut *message_out()
 	{
-		/* By using prepare function, users can modify the request after
+		/* By setting 'prepare' function, users can modify the request after
 		 * the connection is established. */
 		if (this->prepare)
 			this->prepare(this);
@@ -108,7 +108,7 @@ class WFServerTask : public WFNetworkTask<REQ, RESP>
 protected:
 	virtual CommMessageOut *message_out()
 	{
-		/* By using prepare function, users can modify the response before
+		/* By setting 'prepare' function, users can modify the response before
 		 * replying to the client. */
 		if (this->prepare)
 			this->prepare(this);
@@ -120,16 +120,12 @@ protected:
 	virtual void handle(int state, int error);
 
 protected:
-	/* CommSession::get_connection() is supposed to be called only in the
-	 * implementations of it's virtual functions. As a server task, to call
-	 * this function after process() and before callback() is very dangerous
-	 * and should be blocked. */
 	virtual WFConnection *get_connection() const
 	{
-		if (this->processor.task)
+		if (this->processor.task == this)
 			return (WFConnection *)this->CommSession::get_connection();
 
-		errno = EPERM;
+		errno = this->processor.task ? ENOTCONN : EPERM;
 		return NULL;
 	}
 
@@ -138,18 +134,17 @@ protected:
 	{
 		if (this->state == WFT_STATE_TOREPLY)
 		{
-			/* Enable get_connection() again if the reply() call is success. */
 			this->processor.task = this;
 			if (this->scheduler->reply(this) >= 0)
 				return;
 
 			this->state = WFT_STATE_SYS_ERROR;
 			this->error = errno;
-			this->processor.task = NULL;
 		}
 		else
 			this->scheduler->shutdown(this);
 
+		this->processor.task = (WFServerTask *)-1;
 		this->subtask_done();
 	}
 
@@ -166,7 +161,7 @@ protected:
 		if (this->callback)
 			this->callback(this);
 
-		/* Defer deleting the task. */
+		this->processor.task = NULL;
 		return series->pop();
 	}
 
@@ -174,7 +169,7 @@ protected:
 	class Processor : public SubTask
 	{
 	public:
-		Processor(WFServerTask<REQ, RESP> *task,
+		Processor(WFServerTask *task,
 				  std::function<void (WFNetworkTask<REQ, RESP> *)>& proc) :
 			process(proc)
 		{
@@ -184,7 +179,7 @@ protected:
 		virtual void dispatch()
 		{
 			this->process(this->task);
-			this->task = NULL;	/* As a flag. get_conneciton() disabled. */
+			this->task = NULL;	/* As a flag, disable getting connection. */
 			this->subtask_done();
 		}
 
@@ -194,13 +189,13 @@ protected:
 		}
 
 		std::function<void (WFNetworkTask<REQ, RESP> *)>& process;
-		WFServerTask<REQ, RESP> *task;
+		WFServerTask *task;
 	} processor;
 
 	class Series : public SeriesWork
 	{
 	public:
-		Series(WFServerTask<REQ, RESP> *task) :
+		Series(WFServerTask *task) :
 			SeriesWork(&task->processor, nullptr)
 		{
 			this->set_last_task(task);
@@ -212,7 +207,7 @@ protected:
 			delete this->task;
 		}
 
-		WFServerTask<REQ, RESP> *task;
+		WFServerTask *task;
 	};
 
 public: