1 files changed, 92 insertions, 2 deletions

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 142ecd846ccd..9a08f341f0a4 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3281,7 +3281,7 @@ void hci_pend_le_conn_add(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type)
 
 	entry = hci_pend_le_conn_lookup(hdev, addr, addr_type);
 	if (entry)
-		return;
+		goto done;
 
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry) {
@@ -3295,6 +3295,9 @@ void hci_pend_le_conn_add(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type)
 	list_add(&entry->list, &hdev->pend_le_conns);
 
 	BT_DBG("addr %pMR (type %u)", addr, addr_type);
+
+done:
+	hci_update_background_scan(hdev);
 }
 
 /* This function requires the caller holds hdev->lock */
@@ -3304,12 +3307,15 @@ void hci_pend_le_conn_del(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type)
 
 	entry = hci_pend_le_conn_lookup(hdev, addr, addr_type);
 	if (!entry)
-		return;
+		goto done;
 
 	list_del(&entry->list);
 	kfree(entry);
 
 	BT_DBG("addr %pMR (type %u)", addr, addr_type);
+
+done:
+	hci_update_background_scan(hdev);
 }
 
 /* This function requires the caller holds hdev->lock */
@@ -4946,3 +4952,87 @@ void hci_req_add_le_scan_disable(struct hci_request *req)
 	cp.enable = LE_SCAN_DISABLE;
 	hci_req_add(req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(cp), &cp);
 }
+
+static void update_background_scan_complete(struct hci_dev *hdev, u8 status)
+{
+	if (status)
+		BT_DBG("HCI request failed to update background scanning: "
+		       "status 0x%2.2x", status);
+}
+
+/* This function controls the background scanning based on hdev->pend_le_conns
+ * list. If there are pending LE connection we start the background scanning,
+ * otherwise we stop it.
+ *
+ * This function requires the caller holds hdev->lock.
+ */
+void hci_update_background_scan(struct hci_dev *hdev)
+{
+	struct hci_cp_le_set_scan_param param_cp;
+	struct hci_cp_le_set_scan_enable enable_cp;
+	struct hci_request req;
+	struct hci_conn *conn;
+	int err;
+
+	hci_req_init(&req, hdev);
+
+	if (list_empty(&hdev->pend_le_conns)) {
+		/* If there is no pending LE connections, we should stop
+		 * the background scanning.
+		 */
+
+		/* If controller is not scanning we are done. */
+		if (!test_bit(HCI_LE_SCAN, &hdev->dev_flags))
+			return;
+
+		hci_req_add_le_scan_disable(&req);
+
+		BT_DBG("%s stopping background scanning", hdev->name);
+	} else {
+		u8 own_addr_type;
+
+		/* If there is at least one pending LE connection, we should
+		 * keep the background scan running.
+		 */
+
+		/* If controller is already scanning we are done. */
+		if (test_bit(HCI_LE_SCAN, &hdev->dev_flags))
+			return;
+
+		/* If controller is connecting, we should not start scanning
+		 * since some controllers are not able to scan and connect at
+		 * the same time.
+		 */
+		conn = hci_conn_hash_lookup_state(hdev, LE_LINK, BT_CONNECT);
+		if (conn)
+			return;
+
+		/* Set require_privacy to true to avoid identification from
+		 * unknown peer devices. Since this is passive scanning, no
+		 * SCAN_REQ using the local identity should be sent. Mandating
+		 * privacy is just an extra precaution.
+		 */
+		if (hci_update_random_address(&req, true, &own_addr_type))
+			return;
+
+		memset(&param_cp, 0, sizeof(param_cp));
+		param_cp.type = LE_SCAN_PASSIVE;
+		param_cp.interval = cpu_to_le16(hdev->le_scan_interval);
+		param_cp.window = cpu_to_le16(hdev->le_scan_window);
+		param_cp.own_address_type = own_addr_type;
+		hci_req_add(&req, HCI_OP_LE_SET_SCAN_PARAM, sizeof(param_cp),
+			    &param_cp);
+
+		memset(&enable_cp, 0, sizeof(enable_cp));
+		enable_cp.enable = LE_SCAN_ENABLE;
+		enable_cp.filter_dup = LE_SCAN_FILTER_DUP_DISABLE;
+		hci_req_add(&req, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(enable_cp),
+			    &enable_cp);
+
+		BT_DBG("%s starting background scanning", hdev->name);
+	}
+
+	err = hci_req_run(&req, update_background_scan_complete);
+	if (err)
+		BT_ERR("Failed to run HCI request: err %d", err);
+}