Bluetooth: Fix handling of discoverable setting with timeout

The current handling of the discoverable timeout was missing the proper
handling of the timeout when the mode was already set. Now the command
can be used to expire or retrigger the timeout.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

net/bluetooth/mgmt.c

@@ -900,6 +900,17 @@ static int set_discoverable(struct sock *sk, u16 index, void *data, u16 len)
 	}
 
 	if (!!cp->val == test_bit(HCI_DISCOVERABLE, &hdev->dev_flags)) {
+		if (hdev->discov_timeout > 0) {
+			cancel_delayed_work(&hdev->discov_off);
+			hdev->discov_timeout = 0;
+		}
+
+		if (cp->val && timeout > 0) {
+			hdev->discov_timeout = timeout;
+			queue_delayed_work(hdev->workqueue, &hdev->discov_off,
+				msecs_to_jiffies(hdev->discov_timeout * 1000));
+		}
+
 		err = send_settings_rsp(sk, MGMT_OP_SET_DISCOVERABLE, hdev);
 		goto failed;
 	}