Re: [PATCH] HID: force setting drvdata to NULL when removing the driver

From: Benjamin Tissoires
Date: Tue Apr 02 2019 - 09:44:38 EST

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Hi Dmitry,

On Fri, Mar 29, 2019 at 11:26 PM Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> wrote:
>
> Hi Benjamin,
>
> On Thu, Mar 28, 2019 at 8:52 AM Benjamin Tissoires
> <benjamin.tissoires@xxxxxxxxxx> 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.

You are correct (as always ;-P). I'll drop the hid-core changes and
send a v2 ASAP.

Cheers,
Benjamin

>
> Thanks.
>
> --
> Dmitry
>
> On Thu, Mar 28, 2019 at 8:52 AM Benjamin Tissoires
> <benjamin.tissoires@xxxxxxxxxx> 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@xxxxxxxxxx>
> > ---
> > 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

Next message: Dan Murphy: "Re: [PATCH v2 2/3] dt-bindings: backlight: add lm3630a bindings"
Previous message: Ben Hutchings: "[PATCH 3.16 79/99] ext4: make sure enough credits are reserved for dioread_nolock writes"
Next in thread: Hans de Goede: "Re: [PATCH] HID: force setting drvdata to NULL when removing the driver"
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