fs: dlm: use listen sock as dlm running indicator

This patch will switch from dlm_allow_conn to check if dlm lowcomms is
running or not to if we actually have a listen socket set or not. The
list socket will be set and unset in lowcomms start and shutdown
functionality. To synchronize with data_ready() callback we will set the
socket callback to NULL while socket lock is held.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/config.c

@@ -183,7 +183,7 @@ static int dlm_check_protocol_and_dlm_running(unsigned int x)
 		return -EINVAL;
 	}
 
-	if (dlm_allow_conn)
+	if (dlm_lowcomms_is_running())
 		return -EBUSY;
 
 	return 0;
@@ -194,7 +194,7 @@ static int dlm_check_zero_and_dlm_running(unsigned int x)
 	if (!x)
 		return -EINVAL;
 
-	if (dlm_allow_conn)
+	if (dlm_lowcomms_is_running())
 		return -EBUSY;
 
 	return 0;

fs/dlm/lowcomms.c

@@ -176,7 +176,6 @@ static DEFINE_SPINLOCK(dlm_node_addrs_spin);
 static struct listen_connection listen_con;
 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
 static int dlm_local_count;
-int dlm_allow_conn;
 
 /* Work queues */
 static struct workqueue_struct *recv_workqueue;
@@ -191,6 +190,11 @@ static const struct dlm_proto_ops *dlm_proto_ops;
 static void process_recv_sockets(struct work_struct *work);
 static void process_send_sockets(struct work_struct *work);
 
+bool dlm_lowcomms_is_running(void)
+{
+	return !!listen_con.sock;
+}
+
 static void writequeue_entry_ctor(void *data)
 {
 	struct writequeue_entry *entry = data;
@@ -511,9 +515,6 @@ static void lowcomms_data_ready(struct sock *sk)
 
 static void lowcomms_listen_data_ready(struct sock *sk)
 {
-	if (!dlm_allow_conn)
-		return;
-
 	queue_work(recv_workqueue, &listen_con.rwork);
 }
 
@@ -1689,10 +1690,7 @@ void dlm_lowcomms_shutdown(void)
 {
 	int idx;
 
-	/* Set all the flags to prevent any
-	 * socket activity.
-	 */
-	dlm_allow_conn = 0;
+	restore_callbacks(listen_con.sock);
 
 	if (recv_workqueue)
 		flush_workqueue(recv_workqueue);
@@ -1995,8 +1993,6 @@ int dlm_lowcomms_start(void)
 	if (error)
 		goto fail_local;
 
-	dlm_allow_conn = 1;
-
 	/* Start listening */
 	switch (dlm_config.ci_protocol) {
 	case DLM_PROTO_TCP:
@@ -2021,7 +2017,6 @@ int dlm_lowcomms_start(void)
 fail_listen:
 	dlm_proto_ops = NULL;
 fail_proto_ops:
-	dlm_allow_conn = 0;
 	work_stop();
 fail_local:
 	deinit_local();

fs/dlm/lowcomms.h

@@ -29,8 +29,8 @@ static inline int nodeid_hash(int nodeid)
 	return nodeid & (CONN_HASH_SIZE-1);
 }
 
-/* switch to check if dlm is running */
-extern int dlm_allow_conn;
+/* check if dlm is running */
+bool dlm_lowcomms_is_running(void);
 
 int dlm_lowcomms_start(void);
 void dlm_lowcomms_shutdown(void);