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SubjectRe: [PATCH] HID: force setting drvdata to NULL when removing the driver
Hi Benjamin,

On Thu, Mar 28, 2019 at 8:52 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> Or when the probe failed.
>
> This is a common pattern in the HID drivers to reset the drvdata. Some
> do it properly, some do it only in case of failure.
> Anyway, it's never a good thing to have breadcrumbs, so force a clean
> state when removing or when probe is failing.

Just a data point: driver core already clears drvdata, so as long as
dev_get/set_drvdata() is the same as hid_get/set_drvdata() no special
handling is needed in HID core.

Thanks.

--
Dmitry

On Thu, Mar 28, 2019 at 8:52 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> Or when the probe failed.
>
> This is a common pattern in the HID drivers to reset the drvdata. Some
> do it properly, some do it only in case of failure.
> Anyway, it's never a good thing to have breadcrumbs, so force a clean
> state when removing or when probe is failing.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> ---
> drivers/hid/hid-core.c | 2 ++
> drivers/hid/hid-cougar.c | 6 ++----
> drivers/hid/hid-gfrm.c | 7 -------
> drivers/hid/hid-lenovo.c | 2 --
> drivers/hid/hid-logitech-dj.c | 2 --
> drivers/hid/hid-logitech-hidpp.c | 8 +++-----
> drivers/hid/hid-picolcd_core.c | 7 +------
> drivers/hid/hid-sensor-hub.c | 1 -
> drivers/hid/wacom_sys.c | 18 +++++-------------
> 9 files changed, 13 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index b5a8af8daa74..011e49da4d63 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -2203,6 +2203,7 @@ static int hid_device_probe(struct device *dev)
> if (ret) {
> hid_close_report(hdev);
> hdev->driver = NULL;
> + hid_set_drvdata(hdev, NULL);
> }
> }
> unlock:
> @@ -2231,6 +2232,7 @@ static int hid_device_remove(struct device *dev)
> else /* default remove */
> hid_hw_stop(hdev);
> hid_close_report(hdev);
> + hid_set_drvdata(hdev, NULL);
> hdev->driver = NULL;
> }
>
> diff --git a/drivers/hid/hid-cougar.c b/drivers/hid/hid-cougar.c
> index e0bb7b34f3a4..4ff3bc1d25e2 100644
> --- a/drivers/hid/hid-cougar.c
> +++ b/drivers/hid/hid-cougar.c
> @@ -207,7 +207,7 @@ static int cougar_probe(struct hid_device *hdev,
> error = hid_parse(hdev);
> if (error) {
> hid_err(hdev, "parse failed\n");
> - goto fail;
> + return error;
> }
>
> if (hdev->collection->usage == COUGAR_VENDOR_USAGE) {
> @@ -219,7 +219,7 @@ static int cougar_probe(struct hid_device *hdev,
> error = hid_hw_start(hdev, connect_mask);
> if (error) {
> hid_err(hdev, "hw start failed\n");
> - goto fail;
> + return error;
> }
>
> error = cougar_bind_shared_data(hdev, cougar);
> @@ -249,8 +249,6 @@ static int cougar_probe(struct hid_device *hdev,
>
> fail_stop_and_cleanup:
> hid_hw_stop(hdev);
> -fail:
> - hid_set_drvdata(hdev, NULL);
> return error;
> }
>
> diff --git a/drivers/hid/hid-gfrm.c b/drivers/hid/hid-gfrm.c
> index cf477f8c8f4c..1a20997e7750 100644
> --- a/drivers/hid/hid-gfrm.c
> +++ b/drivers/hid/hid-gfrm.c
> @@ -127,12 +127,6 @@ static int gfrm_probe(struct hid_device *hdev, const struct hid_device_id *id)
> return ret;
> }
>
> -static void gfrm_remove(struct hid_device *hdev)
> -{
> - hid_hw_stop(hdev);
> - hid_set_drvdata(hdev, NULL);
> -}
> -
> static const struct hid_device_id gfrm_devices[] = {
> { HID_BLUETOOTH_DEVICE(0x58, 0x2000),
> .driver_data = GFRM100 },
> @@ -146,7 +140,6 @@ static struct hid_driver gfrm_driver = {
> .name = "gfrm",
> .id_table = gfrm_devices,
> .probe = gfrm_probe,
> - .remove = gfrm_remove,
> .input_mapping = gfrm_input_mapping,
> .raw_event = gfrm_raw_event,
> .input_configured = gfrm_input_configured,
> diff --git a/drivers/hid/hid-lenovo.c b/drivers/hid/hid-lenovo.c
> index eacc76d2ab96..cde9d22bb3ec 100644
> --- a/drivers/hid/hid-lenovo.c
> +++ b/drivers/hid/hid-lenovo.c
> @@ -869,8 +869,6 @@ static void lenovo_remove_tpkbd(struct hid_device *hdev)
>
> led_classdev_unregister(&data_pointer->led_micmute);
> led_classdev_unregister(&data_pointer->led_mute);
> -
> - hid_set_drvdata(hdev, NULL);
> }
>
> static void lenovo_remove_cptkbd(struct hid_device *hdev)
> diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
> index 826fa1e1c8d9..a75101293755 100644
> --- a/drivers/hid/hid-logitech-dj.c
> +++ b/drivers/hid/hid-logitech-dj.c
> @@ -1094,7 +1094,6 @@ static int logi_dj_probe(struct hid_device *hdev,
> hid_parse_fail:
> kfifo_free(&djrcv_dev->notif_fifo);
> kfree(djrcv_dev);
> - hid_set_drvdata(hdev, NULL);
> return retval;
>
> }
> @@ -1145,7 +1144,6 @@ static void logi_dj_remove(struct hid_device *hdev)
>
> kfifo_free(&djrcv_dev->notif_fifo);
> kfree(djrcv_dev);
> - hid_set_drvdata(hdev, NULL);
> }
>
> static const struct hid_device_id logi_dj_receivers[] = {
> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
> index 199cc256e9d9..b950a44157a2 100644
> --- a/drivers/hid/hid-logitech-hidpp.c
> +++ b/drivers/hid/hid-logitech-hidpp.c
> @@ -3237,15 +3237,15 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
> if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) {
> ret = wtp_allocate(hdev, id);
> if (ret)
> - goto allocate_fail;
> + return ret;
> } else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560) {
> ret = m560_allocate(hdev);
> if (ret)
> - goto allocate_fail;
> + return ret;
> } else if (hidpp->quirks & HIDPP_QUIRK_CLASS_K400) {
> ret = k400_allocate(hdev);
> if (ret)
> - goto allocate_fail;
> + return ret;
> }
>
> INIT_WORK(&hidpp->work, delayed_work_cb);
> @@ -3343,8 +3343,6 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
> sysfs_remove_group(&hdev->dev.kobj, &ps_attribute_group);
> cancel_work_sync(&hidpp->work);
> mutex_destroy(&hidpp->send_mutex);
> -allocate_fail:
> - hid_set_drvdata(hdev, NULL);
> return ret;
> }
>
> diff --git a/drivers/hid/hid-picolcd_core.c b/drivers/hid/hid-picolcd_core.c
> index c1b29a9eb41a..a5d30f267a7b 100644
> --- a/drivers/hid/hid-picolcd_core.c
> +++ b/drivers/hid/hid-picolcd_core.c
> @@ -550,8 +550,7 @@ static int picolcd_probe(struct hid_device *hdev,
> data = kzalloc(sizeof(struct picolcd_data), GFP_KERNEL);
> if (data == NULL) {
> hid_err(hdev, "can't allocate space for Minibox PicoLCD device data\n");
> - error = -ENOMEM;
> - goto err_no_cleanup;
> + return -ENOMEM;
> }
>
> spin_lock_init(&data->lock);
> @@ -613,9 +612,6 @@ static int picolcd_probe(struct hid_device *hdev,
> hid_hw_stop(hdev);
> err_cleanup_data:
> kfree(data);
> -err_no_cleanup:
> - hid_set_drvdata(hdev, NULL);
> -
> return error;
> }
>
> @@ -651,7 +647,6 @@ static void picolcd_remove(struct hid_device *hdev)
> picolcd_exit_cir(data);
> picolcd_exit_keys(data);
>
> - hid_set_drvdata(hdev, NULL);
> mutex_destroy(&data->mutex);
> /* Finally, clean up the picolcd data itself */
> kfree(data);
> diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
> index 4256fdc5cd6d..a3db5d8b382d 100644
> --- a/drivers/hid/hid-sensor-hub.c
> +++ b/drivers/hid/hid-sensor-hub.c
> @@ -755,7 +755,6 @@ static void sensor_hub_remove(struct hid_device *hdev)
> }
> spin_unlock_irqrestore(&data->lock, flags);
> mfd_remove_devices(&hdev->dev);
> - hid_set_drvdata(hdev, NULL);
> mutex_destroy(&data->mutex);
> }
>
> diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
> index a8633b1437b2..c2fb614bff44 100644
> --- a/drivers/hid/wacom_sys.c
> +++ b/drivers/hid/wacom_sys.c
> @@ -2716,14 +2716,12 @@ static int wacom_probe(struct hid_device *hdev,
> wacom_wac->features = *((struct wacom_features *)id->driver_data);
> features = &wacom_wac->features;
>
> - if (features->check_for_hid_type && features->hid_type != hdev->type) {
> - error = -ENODEV;
> - goto fail;
> - }
> + if (features->check_for_hid_type && features->hid_type != hdev->type)
> + return -ENODEV;
>
> error = kfifo_alloc(&wacom_wac->pen_fifo, WACOM_PKGLEN_MAX, GFP_KERNEL);
> if (error)
> - goto fail;
> + return error;
>
> wacom_wac->hid_data.inputmode = -1;
> wacom_wac->mode_report = -1;
> @@ -2741,12 +2739,12 @@ static int wacom_probe(struct hid_device *hdev,
> error = hid_parse(hdev);
> if (error) {
> hid_err(hdev, "parse failed\n");
> - goto fail;
> + return error;
> }
>
> error = wacom_parse_and_register(wacom, false);
> if (error)
> - goto fail;
> + return error;
>
> if (hdev->bus == BUS_BLUETOOTH) {
> error = device_create_file(&hdev->dev, &dev_attr_speed);
> @@ -2757,10 +2755,6 @@ static int wacom_probe(struct hid_device *hdev,
> }
>
> return 0;
> -
> -fail:
> - hid_set_drvdata(hdev, NULL);
> - return error;
> }
>
> static void wacom_remove(struct hid_device *hdev)
> @@ -2789,8 +2783,6 @@ static void wacom_remove(struct hid_device *hdev)
> wacom_release_resources(wacom);
>
> kfifo_free(&wacom_wac->pen_fifo);
> -
> - hid_set_drvdata(hdev, NULL);
> }
>
> #ifdef CONFIG_PM
> --
> 2.19.2
>


--
Dmitry

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