Bluetooth: Resume advertising after LE connection

When an LE connection request is made, advertising is disabled and never
resumed. When a client has an active advertisement, this is disruptive.
This change adds resume logic for client-configured (non-directed)
advertisements after the connection attempt.

The patch was tested by registering an advertisement, initiating an LE
connection from a remote peer, and verifying that the advertisement is
re-activated after the connection is established. This is performed on
Hatch and Kukui Chromebooks.
Signed-off-by: Daniel Winkler <danielwinkler@google.com>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_conn.c

@@ -758,6 +758,9 @@ static void create_le_conn_complete(struct hci_dev *hdev, u8 status, u16 opcode)
 
 	conn = hci_lookup_le_connect(hdev);
 
+	if (hdev->adv_instance_cnt)
+		hci_req_resume_adv_instances(hdev);
+
 	if (!status) {
 		hci_connect_le_scan_cleanup(conn);
 		goto done;
@@ -1067,10 +1070,11 @@ struct hci_conn *hci_connect_le(struct hci_dev *hdev, bdaddr_t *dst,
 	 * connections most controllers will refuse to connect if
 	 * advertising is enabled, and for slave role connections we
 	 * anyway have to disable it in order to start directed
-	 * advertising.
+	 * advertising. Any registered advertisements will be
+	 * re-enabled after the connection attempt is finished.
 	 */
 	if (hci_dev_test_flag(hdev, HCI_LE_ADV))
-		 __hci_req_disable_advertising(&req);
+		__hci_req_pause_adv_instances(&req);
 
 	/* If requested to connect as slave use directed advertising */
 	if (conn->role == HCI_ROLE_SLAVE) {
@@ -1118,6 +1122,10 @@ struct hci_conn *hci_connect_le(struct hci_dev *hdev, bdaddr_t *dst,
 	err = hci_req_run(&req, create_le_conn_complete);
 	if (err) {
 		hci_conn_del(conn);
+
+		if (hdev->adv_instance_cnt)
+			hci_req_resume_adv_instances(hdev);
+
 		return ERR_PTR(err);
 	}
 

net/bluetooth/hci_request.c

@@ -1123,9 +1123,9 @@ static void cancel_adv_timeout(struct hci_dev *hdev)
 }
 
 /* This function requires the caller holds hdev->lock */
-static void hci_suspend_adv_instances(struct hci_request *req)
+void __hci_req_pause_adv_instances(struct hci_request *req)
 {
-	bt_dev_dbg(req->hdev, "Suspending advertising instances");
+	bt_dev_dbg(req->hdev, "Pausing advertising instances");
 
 	/* Call to disable any advertisements active on the controller.
 	 * This will succeed even if no advertisements are configured.
@@ -1138,7 +1138,7 @@ static void hci_suspend_adv_instances(struct hci_request *req)
 }
 
 /* This function requires the caller holds hdev->lock */
-static void hci_resume_adv_instances(struct hci_request *req)
+static void __hci_req_resume_adv_instances(struct hci_request *req)
 {
 	struct adv_info *adv;
 
@@ -1161,6 +1161,17 @@ static void hci_resume_adv_instances(struct hci_request *req)
 	}
 }
 
+/* This function requires the caller holds hdev->lock */
+int hci_req_resume_adv_instances(struct hci_dev *hdev)
+{
+	struct hci_request req;
+
+	hci_req_init(&req, hdev);
+	__hci_req_resume_adv_instances(&req);
+
+	return hci_req_run(&req, NULL);
+}
+
 static void suspend_req_complete(struct hci_dev *hdev, u8 status, u16 opcode)
 {
 	bt_dev_dbg(hdev, "Request complete opcode=0x%x, status=0x%x", opcode,
@@ -1214,7 +1225,7 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)
 
 		/* Pause other advertisements */
 		if (hdev->adv_instance_cnt)
-			hci_suspend_adv_instances(&req);
+			__hci_req_pause_adv_instances(&req);
 
 		hdev->advertising_paused = true;
 		hdev->advertising_old_state = old_state;
@@ -1279,7 +1290,7 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)
 
 		/* Resume other advertisements */
 		if (hdev->adv_instance_cnt)
-			hci_resume_adv_instances(&req);
+			__hci_req_resume_adv_instances(&req);
 
 		/* Unpause discovery */
 		hdev->discovery_paused = false;

net/bluetooth/hci_request.h

@@ -71,6 +71,8 @@ void hci_req_add_le_passive_scan(struct hci_request *req);
 void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next);
 
 void hci_req_disable_address_resolution(struct hci_dev *hdev);
+void __hci_req_pause_adv_instances(struct hci_request *req);
+int hci_req_resume_adv_instances(struct hci_dev *hdev);
 void hci_req_reenable_advertising(struct hci_dev *hdev);
 void __hci_req_enable_advertising(struct hci_request *req);
 void __hci_req_disable_advertising(struct hci_request *req);