Bluetooth: mgmt: multi adv for set_advertising*()

The set_advertising() and set_advertising_complete() methods rely on
the now obsolete hci_dev->adv_instance structure. We replace this
reference by an equivalent access to the newly introduced dynamic
advertising instance list.

This patch introduces a helper function that schedules an advertising
instance correctly calculating advertising timing based on the timeout
and duration settings of the instance. Scheduling is factored into
its own function for readability and code sharing.

Signed-off-by: Florian Grandel <fgrandel@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/mgmt.c

@@ -1471,6 +1471,73 @@ static void advertising_removed(struct sock *sk, struct hci_dev *hdev,
 	mgmt_event(MGMT_EV_ADVERTISING_REMOVED, hdev, &ev, sizeof(ev), sk);
 }
 
+static int schedule_adv_instance(struct hci_request *req, u8 instance,
+				 bool force) {
+	struct hci_dev *hdev = req->hdev;
+	struct adv_info *adv_instance = NULL;
+	u16 timeout;
+
+	if (hci_dev_test_flag(hdev, HCI_ADVERTISING) ||
+	    !hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE))
+		return -EPERM;
+
+	if (hdev->adv_instance_timeout)
+		return -EBUSY;
+
+	adv_instance = hci_find_adv_instance(hdev, instance);
+	if (!adv_instance)
+		return -ENOENT;
+
+	/* A zero timeout means unlimited advertising. As long as there is
+	 * only one instance, duration should be ignored. We still set a timeout
+	 * in case further instances are being added later on.
+	 *
+	 * If the remaining lifetime of the instance is more than the duration
+	 * then the timeout corresponds to the duration, otherwise it will be
+	 * reduced to the remaining instance lifetime.
+	 */
+	if (adv_instance->timeout == 0 ||
+	    adv_instance->duration <= adv_instance->remaining_time)
+		timeout = adv_instance->duration;
+	else
+		timeout = adv_instance->remaining_time;
+
+	/* The remaining time is being reduced unless the instance is being
+	 * advertised without time limit.
+	 */
+	if (adv_instance->timeout)
+		adv_instance->remaining_time =
+				adv_instance->remaining_time - timeout;
+
+	hdev->adv_instance_timeout = timeout;
+	queue_delayed_work(hdev->workqueue,
+			   &hdev->adv_instance_expire,
+			   msecs_to_jiffies(timeout * 1000));
+
+	/* If we're just re-scheduling the same instance again then do not
+	 * execute any HCI commands. This happens when a single instance is
+	 * being advertised.
+	 */
+	if (!force && hdev->cur_adv_instance == instance &&
+	    hci_dev_test_flag(hdev, HCI_LE_ADV))
+		return 0;
+
+	hdev->cur_adv_instance = instance;
+	update_adv_data(req);
+	update_scan_rsp_data(req);
+	enable_advertising(req);
+
+	return 0;
+}
+
+static void cancel_adv_timeout(struct hci_dev *hdev)
+{
+	if (hdev->adv_instance_timeout) {
+		hdev->adv_instance_timeout = 0;
+		cancel_delayed_work(&hdev->adv_instance_expire);
+	}
+}
+
 static void clear_adv_instance(struct hci_dev *hdev)
 {
 	struct hci_request req;
@@ -4681,6 +4748,9 @@ static void set_advertising_complete(struct hci_dev *hdev, u8 status,
 {
 	struct cmd_lookup match = { NULL, hdev };
 	struct hci_request req;
+	u8 instance;
+	struct adv_info *adv_instance;
+	int err;
 
 	hci_dev_lock(hdev);
 
@@ -4706,18 +4776,31 @@ static void set_advertising_complete(struct hci_dev *hdev, u8 status,
 		sock_put(match.sk);
 
 	/* If "Set Advertising" was just disabled and instance advertising was
-	 * set up earlier, then enable the advertising instance.
+	 * set up earlier, then re-enable multi-instance advertising.
 	 */
 	if (hci_dev_test_flag(hdev, HCI_ADVERTISING) ||
-	    !hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE))
+	    !hci_dev_test_flag(hdev, HCI_ADVERTISING_INSTANCE) ||
+	    list_empty(&hdev->adv_instances))
 		goto unlock;
 
+	instance = hdev->cur_adv_instance;
+	if (!instance) {
+		adv_instance = list_first_entry_or_null(&hdev->adv_instances,
+							struct adv_info, list);
+		if (!adv_instance)
+			goto unlock;
+
+		instance = adv_instance->instance;
+	}
+
 	hci_req_init(&req, hdev);
 
-	update_adv_data(&req);
-	enable_advertising(&req);
+	err = schedule_adv_instance(&req, instance, true);
+
+	if (!err)
+		err = hci_req_run(&req, enable_advertising_instance);
 
-	if (hci_req_run(&req, enable_advertising_instance) < 0)
+	if (err)
 		BT_ERR("Failed to re-configure advertising");
 
 unlock:
@@ -4802,8 +4885,13 @@ static int set_advertising(struct sock *sk, struct hci_dev *hdev, void *data,
 	else
 		hci_dev_clear_flag(hdev, HCI_ADVERTISING_CONNECTABLE);
 
+	cancel_adv_timeout(hdev);
+
 	if (val) {
-		/* Switch to instance "0" for the Set Advertising setting. */
+		/* Switch to instance "0" for the Set Advertising setting.
+		 * We cannot use update_[adv|scan_rsp]_data() here as the
+		 * HCI_ADVERTISING flag is not yet set.
+		 */
 		update_inst_adv_data(&req, 0x00);
 		update_inst_scan_rsp_data(&req, 0x00);
 		enable_advertising(&req);