linux-kernel - Re: [PATCH] iio: cros_ec_accel_legacy: Refactor code in cros_ec_accel_legacy

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Date:   Wed, 20 Feb 2019 23:00:29 -0800
From:   Kees Cook <keescook@...omium.org>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Benson Leung <bleung@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Guenter Roeck <groeck@...omium.org>, linux-iio@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Gwendal Grignou <gwendal@...omium.org>
Subject: Re: [PATCH] iio: cros_ec_accel_legacy: Refactor code in cros_ec_accel_legacy_probe

On Wed, Feb 20, 2019 at 6:06 PM Gustavo A. R. Silva
<gustavo@...eddedor.com> wrote:
>
> Refactor some code in order to fix both the technical implementation
> and the following warnings:
>
> drivers/iio/accel/cros_ec_accel_legacy.c: In function ‘cros_ec_accel_legacy_probe’:
> drivers/iio/accel/cros_ec_accel_legacy.c:387:36: warning: this statement may fall through [-Wimplicit-fallthrough=]
>     ec_accel_channels[X].scan_index = Y;
>     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
> drivers/iio/accel/cros_ec_accel_legacy.c:388:3: note: here
>    case Y:
>    ^~~~
> drivers/iio/accel/cros_ec_accel_legacy.c:389:36: warning: this statement may fall through [-Wimplicit-fallthrough=]
>     ec_accel_channels[Y].scan_index = X;
>     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
> drivers/iio/accel/cros_ec_accel_legacy.c:390:3: note: here
>    case Z:
>    ^~~~
>
> Notice that neither the for loop nor the switch statement is needed.
> Also, "state->sign[Y] = 1" should be unconditional.
>
> This patch is part of the ongoing efforts to enable
> -Wimplicit-fallthrough.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>

Acked-by: Kees Cook <keescook@...omium.org>

-Kees

> ---
>  drivers/iio/accel/cros_ec_accel_legacy.c | 27 +++++++++++-------------
>  1 file changed, 12 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/iio/accel/cros_ec_accel_legacy.c b/drivers/iio/accel/cros_ec_accel_legacy.c
> index 063e89eff791..021f9f5cd3bb 100644
> --- a/drivers/iio/accel/cros_ec_accel_legacy.c
> +++ b/drivers/iio/accel/cros_ec_accel_legacy.c
> @@ -353,7 +353,7 @@ static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
>         struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
>         struct iio_dev *indio_dev;
>         struct cros_ec_accel_legacy_state *state;
> -       int ret, i;
> +       int ret;
>
>         if (!ec || !ec->ec_dev) {
>                 dev_warn(&pdev->dev, "No EC device found.\n");
> @@ -381,20 +381,17 @@ static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
>          * Present the channel using HTML5 standard:
>          * need to invert X and Y and invert some lid axis.
>          */
> -       for (i = X ; i < MAX_AXIS; i++) {
> -               switch (i) {
> -               case X:
> -                       ec_accel_channels[X].scan_index = Y;
> -               case Y:
> -                       ec_accel_channels[Y].scan_index = X;
> -               case Z:
> -                       ec_accel_channels[Z].scan_index = Z;
> -               }
> -               if (state->sensor_num == MOTIONSENSE_LOC_LID && i != Y)
> -                       state->sign[i] = -1;
> -               else
> -                       state->sign[i] = 1;
> -       }
> +       ec_accel_channels[X].scan_index = Y;
> +       ec_accel_channels[Y].scan_index = X;
> +       ec_accel_channels[Z].scan_index = Z;
> +
> +       state->sign[Y] = 1;
> +
> +       if (state->sensor_num == MOTIONSENSE_LOC_LID)
> +               state->sign[X] = state->sign[Z] = -1;
> +       else
> +               state->sign[X] = state->sign[Z] = 1;
> +
>         indio_dev->num_channels = ARRAY_SIZE(ec_accel_channels);
>         indio_dev->dev.parent = &pdev->dev;
>         indio_dev->info = &cros_ec_accel_legacy_info;
> --
> 2.20.1
>


-- 
Kees Cook