[PATCH 1/2] iio: hid-sensor-gyro-3d: move iio_device_register() to end of probe()

[Bhargav Joshi]

Currently, calling iio_device_register() before
sensor_hub_register_callback() may create a race condition where the
device is exposed to userspace before callbacks are wired.

Move iio_device_register() to the end of the probe() function to prevent
race condition.

Consequently, update the error handling path in probe() and in remove()
ensuring that iio_device_unregister() is called first to cut off
userspace access before the hardware callbacks are removed.

Signed-off-by: Bhargav Joshi <rougueprince47@xxxxxxxxx>
---
 drivers/iio/gyro/hid-sensor-gyro-3d.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/gyro/hid-sensor-gyro-3d.c b/drivers/iio/gyro/hid-sensor-gyro-3d.c
index c43990c518f7..8e3628cd8529 100644
--- a/drivers/iio/gyro/hid-sensor-gyro-3d.c
+++ b/drivers/iio/gyro/hid-sensor-gyro-3d.c
@@ -333,12 +333,6 @@ static int hid_gyro_3d_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = iio_device_register(indio_dev);
-	if (ret) {
-		dev_err(&pdev->dev, "device register failed\n");
-		goto error_remove_trigger;
-	}
-
 	gyro_state->callbacks.send_event = gyro_3d_proc_event;
 	gyro_state->callbacks.capture_sample = gyro_3d_capture_sample;
 	gyro_state->callbacks.pdev = pdev;
@@ -346,13 +340,19 @@ static int hid_gyro_3d_probe(struct platform_device *pdev)
 					&gyro_state->callbacks);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "callback reg failed\n");
-		goto error_iio_unreg;
+		goto error_remove_trigger;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "device register failed\n");
+		goto error_remove_callback;
 	}
 
 	return ret;
 
-error_iio_unreg:
-	iio_device_unregister(indio_dev);
+error_remove_callback:
+	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_GYRO_3D);
 error_remove_trigger:
 	hid_sensor_remove_trigger(indio_dev, &gyro_state->common_attributes);
 	return ret;
@@ -365,8 +365,8 @@ static void hid_gyro_3d_remove(struct platform_device *pdev)
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 	struct gyro_3d_state *gyro_state = iio_priv(indio_dev);
 
-	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_GYRO_3D);
 	iio_device_unregister(indio_dev);
+	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_GYRO_3D);
 	hid_sensor_remove_trigger(indio_dev, &gyro_state->common_attributes);
 }
 
-- 
2.53.0