Re: [PATCH v3 1/2] HID: i2c-hid: Use devm to allocate i2c_hid struct

From: Benjamin Tissoires
Date: Fri Jun 22 2018 - 03:16:35 EST


On Fri, Jun 22, 2018 at 4:27 AM, Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:
> Use devm here to save some lines and prepare for bulk regulator usage in
> this driver. Otherwise, when we devm bulk get regulators we'll free the
> containing i2c_hid structure and try to put regulator pointers from
> freed memory.
>
> Cc: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Cc: Dmitry Torokhov <dtor@xxxxxxxxxxxx>
> Cc: Doug Anderson <dianders@xxxxxxxxxxxx>
> Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> ---
> drivers/hid/i2c-hid/i2c-hid.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index c1652bb7bd15..c7d6738dc524 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -1002,18 +1002,18 @@ static int i2c_hid_probe(struct i2c_client *client,
> return client->irq;
> }
>
> - ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
> + ihid = devm_kzalloc(&client->dev, sizeof(*ihid), GFP_KERNEL);

IIRC, I never made the switch towards devm for i2c_hid because at the
time there was a "all or nothing" rule regarding devm.
But given that the regulator already has a devm inside, I think we are
screwed here and we should probably try to devm-ize the module.

I seem to remember that someone posted a devm version of
hid_allocate_device/hid-add_device, but I don't think this ever went
upstream (because no use).

Otherwise, for the series:
Acked-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>

Cheers,
Benjamin



> if (!ihid)
> return -ENOMEM;
>
> if (client->dev.of_node) {
> ret = i2c_hid_of_probe(client, &ihid->pdata);
> if (ret)
> - goto err;
> + return ret;
> } else if (!platform_data) {
> ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
> if (ret)
> - goto err;
> + return ret;
> } else {
> ihid->pdata = *platform_data;
> }
> @@ -1126,7 +1126,6 @@ static int i2c_hid_probe(struct i2c_client *client,
>
> err:
> i2c_hid_free_buffers(ihid);
> - kfree(ihid);
> return ret;
> }
>
> @@ -1150,8 +1149,6 @@ static int i2c_hid_remove(struct i2c_client *client)
>
> regulator_disable(ihid->pdata.supply);
>
> - kfree(ihid);
> -
> return 0;
> }
>
> --
> Sent by a computer through tubes
>