Bluetooth: advmon offload MSFT handle controller reset

When the controller is powered off, the registered advertising monitor
is removed from the controller. This patch handles the re-registration
of those monitors when the power is on.
Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
Reviewed-by: Yun-Hao Chung <howardchung@google.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/msft.c

@@ -82,8 +82,12 @@ struct msft_data {
 	struct list_head handle_map;
 	__u16 pending_add_handle;
 	__u16 pending_remove_handle;
+	__u8 reregistering;
 };
 
+static int __msft_add_monitor_pattern(struct hci_dev *hdev,
+				      struct adv_monitor *monitor);
+
 bool msft_monitor_supported(struct hci_dev *hdev)
 {
 	return !!(msft_get_features(hdev) & MSFT_FEATURE_MASK_LE_ADV_MONITOR);
@@ -134,6 +138,35 @@ static bool read_supported_features(struct hci_dev *hdev,
 	return false;
 }
 
+/* This function requires the caller holds hdev->lock */
+static void reregister_monitor_on_restart(struct hci_dev *hdev, int handle)
+{
+	struct adv_monitor *monitor;
+	struct msft_data *msft = hdev->msft_data;
+	int err;
+
+	while (1) {
+		monitor = idr_get_next(&hdev->adv_monitors_idr, &handle);
+		if (!monitor) {
+			/* All monitors have been reregistered */
+			msft->reregistering = false;
+			hci_update_background_scan(hdev);
+			return;
+		}
+
+		msft->pending_add_handle = (u16)handle;
+		err = __msft_add_monitor_pattern(hdev, monitor);
+
+		/* If success, we return and wait for monitor added callback */
+		if (!err)
+			return;
+
+		/* Otherwise remove the monitor and keep registering */
+		hci_free_adv_monitor(hdev, monitor);
+		handle++;
+	}
+}
+
 void msft_do_open(struct hci_dev *hdev)
 {
 	struct msft_data *msft;
@@ -154,12 +187,18 @@ void msft_do_open(struct hci_dev *hdev)
 
 	INIT_LIST_HEAD(&msft->handle_map);
 	hdev->msft_data = msft;
+
+	if (msft_monitor_supported(hdev)) {
+		msft->reregistering = true;
+		reregister_monitor_on_restart(hdev, 0);
+	}
 }
 
 void msft_do_close(struct hci_dev *hdev)
 {
 	struct msft_data *msft = hdev->msft_data;
 	struct msft_monitor_advertisement_handle_data *handle_data, *tmp;
+	struct adv_monitor *monitor;
 
 	if (!msft)
 		return;
@@ -169,6 +208,12 @@ void msft_do_close(struct hci_dev *hdev)
 	hdev->msft_data = NULL;
 
 	list_for_each_entry_safe(handle_data, tmp, &msft->handle_map, list) {
+		monitor = idr_find(&hdev->adv_monitors_idr,
+				   handle_data->mgmt_handle);
+
+		if (monitor && monitor->state == ADV_MONITOR_STATE_OFFLOADED)
+			monitor->state = ADV_MONITOR_STATE_REGISTERED;
+
 		list_del(&handle_data->list);
 		kfree(handle_data);
 	}
@@ -282,9 +327,15 @@ static void msft_le_monitor_advertisement_cb(struct hci_dev *hdev,
 	if (status && monitor)
 		hci_free_adv_monitor(hdev, monitor);
 
+	/* If in restart/reregister sequence, keep registering. */
+	if (msft->reregistering)
+		reregister_monitor_on_restart(hdev,
+					      msft->pending_add_handle + 1);
+
 	hci_dev_unlock(hdev);
 
-	hci_add_adv_patterns_monitor_complete(hdev, status);
+	if (!msft->reregistering)
+		hci_add_adv_patterns_monitor_complete(hdev, status);
 }
 
 static void msft_le_cancel_monitor_advertisement_cb(struct hci_dev *hdev,
@@ -374,7 +425,8 @@ static bool msft_monitor_pattern_valid(struct adv_monitor *monitor)
 }
 
 /* This function requires the caller holds hdev->lock */
-int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor)
+static int __msft_add_monitor_pattern(struct hci_dev *hdev,
+				      struct adv_monitor *monitor)
 {
 	struct msft_cp_le_monitor_advertisement *cp;
 	struct msft_le_monitor_advertisement_pattern_data *pattern_data;
@@ -387,9 +439,6 @@ int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor)
 	u8 pattern_count = 0;
 	int err = 0;
 
-	if (!msft)
-		return -EOPNOTSUPP;
-
 	if (!msft_monitor_pattern_valid(monitor))
 		return -EINVAL;
 
@@ -434,6 +483,20 @@ int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor)
 	return err;
 }
 
+/* This function requires the caller holds hdev->lock */
+int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor)
+{
+	struct msft_data *msft = hdev->msft_data;
+
+	if (!msft)
+		return -EOPNOTSUPP;
+
+	if (msft->reregistering)
+		return -EBUSY;
+
+	return __msft_add_monitor_pattern(hdev, monitor);
+}
+
 /* This function requires the caller holds hdev->lock */
 int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor,
 			u16 handle)
@@ -447,6 +510,9 @@ int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor,
 	if (!msft)
 		return -EOPNOTSUPP;
 
+	if (msft->reregistering)
+		return -EBUSY;
+
 	handle_data = msft_find_handle_data(hdev, monitor->handle, true);
 
 	/* If no matched handle, just remove without telling controller */