[BLUETOOTH]: Add conn add/del workqueues to avoid connection fail.

The bluetooth hci_conn sysfs add/del executed in the default
workqueue.  If the del_conn is executed after the new add_conn with
same target, add_conn will failed with warning of "same kobject name".

Here add btaddconn & btdelconn workqueues, flush the btdelconn
workqueue in the add_conn function to avoid the issue.
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bluetooth/hci_sysfs.c

@@ -12,6 +12,8 @@
 #undef  BT_DBG
 #define BT_DBG(D...)
 #endif
+static struct workqueue_struct *btaddconn;
+static struct workqueue_struct *btdelconn;
 
 static inline char *typetostr(int type)
 {
@@ -279,6 +281,7 @@ static void add_conn(struct work_struct *work)
 	struct hci_conn *conn = container_of(work, struct hci_conn, work);
 	int i;
 
+	flush_workqueue(btdelconn);
 	if (device_add(&conn->dev) < 0) {
 		BT_ERR("Failed to register connection device");
 		return;
@@ -313,6 +316,7 @@ void hci_conn_add_sysfs(struct hci_conn *conn)
 
 	INIT_WORK(&conn->work, add_conn);
 
+	queue_work(btaddconn, &conn->work);
 	schedule_work(&conn->work);
 }
 
@@ -349,6 +353,7 @@ void hci_conn_del_sysfs(struct hci_conn *conn)
 
 	INIT_WORK(&conn->work, del_conn);
 
+	queue_work(btdelconn, &conn->work);
 	schedule_work(&conn->work);
 }
 
@@ -398,31 +403,52 @@ int __init bt_sysfs_init(void)
 {
 	int err;
 
+	btaddconn = create_singlethread_workqueue("btaddconn");
+	if (!btaddconn) {
+		err = -ENOMEM;
+		goto out;
+	}
+	btdelconn = create_singlethread_workqueue("btdelconn");
+	if (!btdelconn) {
+		err = -ENOMEM;
+		goto out_del;
+	}
+
 	bt_platform = platform_device_register_simple("bluetooth", -1, NULL, 0);
-	if (IS_ERR(bt_platform))
-		return PTR_ERR(bt_platform);
+	if (IS_ERR(bt_platform)) {
+		err = PTR_ERR(bt_platform);
+		goto out_platform;
+	}
 
 	err = bus_register(&bt_bus);
-	if (err < 0) {
-		platform_device_unregister(bt_platform);
-		return err;
-	}
+	if (err < 0)
+		goto out_bus;
 
 	bt_class = class_create(THIS_MODULE, "bluetooth");
 	if (IS_ERR(bt_class)) {
-		bus_unregister(&bt_bus);
-		platform_device_unregister(bt_platform);
-		return PTR_ERR(bt_class);
+		err = PTR_ERR(bt_class);
+		goto out_class;
 	}
 
 	return 0;
+
+out_class:
+	bus_unregister(&bt_bus);
+out_bus:
+	platform_device_unregister(bt_platform);
+out_platform:
+	destroy_workqueue(btdelconn);
+out_del:
+	destroy_workqueue(btaddconn);
+out:
+	return err;
 }
 
 void bt_sysfs_cleanup(void)
 {
+	destroy_workqueue(btaddconn);
+	destroy_workqueue(btdelconn);
 	class_destroy(bt_class);
-
 	bus_unregister(&bt_bus);
-
 	platform_device_unregister(bt_platform);
 }