Bluetooth: 6LoWPAN: Remove network devices when unloading

When the module is unloaded, unregister the network device
so that the system does not try to access non-existing device.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index ba6c64163685..5a7f81df603c 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -607,6 +607,17 @@ static void ifup(struct net_device *netdev)
         rtnl_unlock();
 }
 
+static void ifdown(struct net_device *netdev)
+{
+        int err;
+
+        rtnl_lock();
+        err = dev_close(netdev);
+        if (err < 0)
+                BT_INFO("iface %s cannot be closed (%d)", netdev->name, err);
+        rtnl_unlock();
+}
+
 static void do_notify_peers(struct work_struct *work)
 {
         struct lowpan_dev *dev = container_of(work, struct lowpan_dev,
@@ -829,6 +840,8 @@ static void chan_close_cb(struct l2cap_chan *chan)
 
                 cancel_delayed_work_sync(&dev->notify_peers);
 
+                ifdown(dev->netdev);
+
                 if (!removed) {
                         INIT_WORK(&entry->delete_netdev, delete_netdev);
                         schedule_work(&entry->delete_netdev);
@@ -1186,6 +1199,43 @@ static const struct file_operations lowpan_control_fops = {
         .release        = single_release,
 };
 
+static void disconnect_devices(void)
+{
+        struct lowpan_dev *entry, *tmp, *new_dev;
+        struct list_head devices;
+        unsigned long flags;
+
+        INIT_LIST_HEAD(&devices);
+
+        /* We make a separate list of devices because the unregister_netdev()
+         * will call device_event() which will also want to modify the same
+         * devices list.
+         */
+
+        read_lock_irqsave(&devices_lock, flags);
+
+        list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices, list) {
+                new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
+                if (!new_dev)
+                        break;
+
+                new_dev->netdev = entry->netdev;
+                INIT_LIST_HEAD(&new_dev->list);
+
+                list_add(&new_dev->list, &devices);
+        }
+
+        read_unlock_irqrestore(&devices_lock, flags);
+
+        list_for_each_entry_safe(entry, tmp, &devices, list) {
+                ifdown(entry->netdev);
+                BT_DBG("Unregistering netdev %s %p",
+                       entry->netdev->name, entry->netdev);
+                unregister_netdev(entry->netdev);
+                kfree(entry);
+        }
+}
+
 static int device_event(struct notifier_block *unused,
                         unsigned long event, void *ptr)
 {
@@ -1202,6 +1252,8 @@ static int device_event(struct notifier_block *unused,
                 list_for_each_entry_safe(entry, tmp, &bt_6lowpan_devices,
                                          list) {
                         if (entry->netdev == netdev) {
+                                BT_DBG("Unregistered netdev %s %p",
+                                       netdev->name, netdev);
                                 list_del(&entry->list);
                                 kfree(entry);
                                 break;
@@ -1240,6 +1292,8 @@ static void __exit bt_6lowpan_exit(void)
                 l2cap_chan_put(listen_chan);
         }
 
+        disconnect_devices();
+
         unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
 }