Bluetooth: Pause discovery and advertising during suspend

To prevent spurious wake ups, we disable any discovery or advertising
when we enter suspend and restore it when we exit suspend. While paused,
we disable any management requests to modify discovery or advertising.

Signed-off-by: Abhishek Pandit-Subedi <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

include/net/bluetooth/hci_core.h

···
 #define SUSPEND_NOTIFIER_TIMEOUT	msecs_to_jiffies(2000) /* 2 seconds */
 
 enum suspend_tasks {
+	SUSPEND_PAUSE_DISCOVERY,
+	SUSPEND_UNPAUSE_DISCOVERY,
+
+	SUSPEND_PAUSE_ADVERTISING,
+	SUSPEND_UNPAUSE_ADVERTISING,
+
 	SUSPEND_SCAN_DISABLE,
 	SUSPEND_SCAN_ENABLE,
 	SUSPEND_DISCONNECTING,
···
 	void			*smp_bredr_data;
 
 	struct discovery_state	discovery;
+
+	int			discovery_old_state;
+	bool			discovery_paused;
+	int			advertising_old_state;
+	bool			advertising_paused;
 
 	struct notifier_block	suspend_notifier;
 	struct work_struct	suspend_prepare;

net/bluetooth/hci_request.c

···
 /* Call with hci_dev_lock */
 void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)
 {
+	int old_state;
 	struct hci_conn *conn;
 	struct hci_request req;
 	u8 page_scan;
···
 		/* Mark device as suspended */
 		hdev->suspended = true;
 
+		/* Pause discovery if not already stopped */
+		old_state = hdev->discovery.state;
+		if (old_state != DISCOVERY_STOPPED) {
+			set_bit(SUSPEND_PAUSE_DISCOVERY, hdev->suspend_tasks);
+			hci_discovery_set_state(hdev, DISCOVERY_STOPPING);
+			queue_work(hdev->req_workqueue, &hdev->discov_update);
+		}
+
+		hdev->discovery_paused = true;
+		hdev->discovery_old_state = old_state;
+
+		/* Stop advertising */
+		old_state = hci_dev_test_flag(hdev, HCI_ADVERTISING);
+		if (old_state) {
+			set_bit(SUSPEND_PAUSE_ADVERTISING, hdev->suspend_tasks);
+			cancel_delayed_work(&hdev->discov_off);
+			queue_delayed_work(hdev->req_workqueue,
+					   &hdev->discov_off, 0);
+		}
+
+		hdev->advertising_paused = true;
+		hdev->advertising_old_state = old_state;
 		/* Disable page scan */
 		page_scan = SCAN_DISABLED;
 		hci_req_add(&req, HCI_OP_WRITE_SCAN_ENABLE, 1, &page_scan);
···
 		hci_req_clear_event_filter(&req);
 		/* Reset passive/background scanning to normal */
 		hci_req_config_le_suspend_scan(&req);
+
+		/* Unpause advertising */
+		hdev->advertising_paused = false;
+		if (hdev->advertising_old_state) {
+			set_bit(SUSPEND_UNPAUSE_ADVERTISING,
+				hdev->suspend_tasks);
+			hci_dev_set_flag(hdev, HCI_ADVERTISING);
+			queue_work(hdev->req_workqueue,
+				   &hdev->discoverable_update);
+			hdev->advertising_old_state = 0;
+		}
+
+		/* Unpause discovery */
+		hdev->discovery_paused = false;
+		if (hdev->discovery_old_state != DISCOVERY_STOPPED &&
+		    hdev->discovery_old_state != DISCOVERY_STOPPING) {
+			set_bit(SUSPEND_UNPAUSE_DISCOVERY, hdev->suspend_tasks);
+			hci_discovery_set_state(hdev, DISCOVERY_STARTING);
+			queue_work(hdev->req_workqueue, &hdev->discov_update);
+		}
+
 		hci_req_run(&req, suspend_req_complete);
 	}
 

net/bluetooth/mgmt.c

···
 		goto failed;
 	}
 
+	if (hdev->advertising_paused) {
+		err = mgmt_cmd_status(sk, hdev->id, MGMT_OP_SET_DISCOVERABLE,
+				      MGMT_STATUS_BUSY);
+		goto failed;
+	}
+
 	if (!hdev_is_powered(hdev)) {
 		bool changed = false;
 
···
 	}
 
 	hci_dev_unlock(hdev);
+
+	/* Handle suspend notifier */
+	if (test_and_clear_bit(SUSPEND_UNPAUSE_DISCOVERY,
+			       hdev->suspend_tasks)) {
+		bt_dev_dbg(hdev, "Unpaused discovery");
+		wake_up(&hdev->suspend_wait_q);
+	}
 }
 
 static bool discovery_type_is_valid(struct hci_dev *hdev, uint8_t type,
···
 
 	if (!discovery_type_is_valid(hdev, cp->type, &status)) {
 		err = mgmt_cmd_complete(sk, hdev->id, op, status,
+					&cp->type, sizeof(cp->type));
+		goto failed;
+	}
+
+	/* Can't start discovery when it is paused */
+	if (hdev->discovery_paused) {
+		err = mgmt_cmd_complete(sk, hdev->id, op, MGMT_STATUS_BUSY,
 					&cp->type, sizeof(cp->type));
 		goto failed;
 	}
···
 	}
 
 	hci_dev_unlock(hdev);
+
+	/* Handle suspend notifier */
+	if (test_and_clear_bit(SUSPEND_PAUSE_DISCOVERY, hdev->suspend_tasks)) {
+		bt_dev_dbg(hdev, "Paused discovery");
+		wake_up(&hdev->suspend_wait_q);
+	}
 }
 
 static int stop_discovery(struct sock *sk, struct hci_dev *hdev, void *data,
···
 	if (match.sk)
 		sock_put(match.sk);
 
+	/* Handle suspend notifier */
+	if (test_and_clear_bit(SUSPEND_PAUSE_ADVERTISING,
+			       hdev->suspend_tasks)) {
+		bt_dev_dbg(hdev, "Paused advertising");
+		wake_up(&hdev->suspend_wait_q);
+	} else if (test_and_clear_bit(SUSPEND_UNPAUSE_ADVERTISING,
+				      hdev->suspend_tasks)) {
+		bt_dev_dbg(hdev, "Unpaused advertising");
+		wake_up(&hdev->suspend_wait_q);
+	}
+
 	/* If "Set Advertising" was just disabled and instance advertising was
 	 * set up earlier, then re-enable multi-instance advertising.
 	 */
···
 	if (cp->val != 0x00 && cp->val != 0x01 && cp->val != 0x02)
 		return mgmt_cmd_status(sk, hdev->id, MGMT_OP_SET_ADVERTISING,
 				       MGMT_STATUS_INVALID_PARAMS);
+
+	if (hdev->advertising_paused)
+		return mgmt_cmd_status(sk, hdev->id, MGMT_OP_SET_ADVERTISING,
+				       MGMT_STATUS_BUSY);
 
 	hci_dev_lock(hdev);