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References: <20200724183954.1.I2e29ae25368ba8a72a9e44121cfbc36ead8ecc6b@changeid> <20200728151258.1222876-1-campello@chromium.org> <20200728091057.10.Ibe84fae61cd914c116e6d59ffeb644f1cbecd601@changeid>
Subject: Re: [PATCH 10/15] iio: sx9310: Simplify error return handling
From:   Stephen Boyd <swboyd@chromium.org>
Cc:     Jonathan Cameron <jic23@kernel.org>,
        Daniel Campello <campello@chromium.org>,
        Douglas Anderson <dianders@chromium.org>,
        Enrico Granata <egranata@chromium.org>,
        Hartmut Knaack <knaack.h@gmx.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        linux-iio@vger.kernel.org
To:     Daniel Campello <campello@chromium.org>,
        LKML <devicetree@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Date:   Tue, 28 Jul 2020 12:40:37 -0700
Message-ID: <159596523705.1360974.7169089810545711557@swboyd.mtv.corp.google.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Quoting Daniel Campello (2020-07-28 08:12:53)
> @@ -368,13 +368,13 @@ static int sx9310_wait_for_sample(struct sx9310_dat=
a *data)
>  static int sx9310_read_proximity(struct sx9310_data *data,
>                                  const struct iio_chan_spec *chan, int *v=
al)
>  {
> -       int ret =3D 0;
> +       int ret;
>         __be16 rawval;
> =20
>         mutex_lock(&data->mutex);
> =20
>         ret =3D sx9310_get_read_channel(data, chan->channel);
> -       if (ret < 0)
> +       if (ret)
>                 goto out;
> =20
>         if (data->client->irq) {
> @@ -394,11 +394,11 @@ static int sx9310_read_proximity(struct sx9310_data=
 *data,
> =20
>         mutex_lock(&data->mutex);
> =20
> -       if (ret < 0)
> +       if (ret)
>                 goto out_disable_irq;

Why is this condition checked after grabbing the mutex? Shouldn't it be
checked before grabbing the mutex? Or is that supposed to be a
mutex_unlock()?

> =20
>         ret =3D sx9310_read_prox_data(data, chan, &rawval);
> -       if (ret < 0)
> +       if (ret)
>                 goto out_disable_irq;
> =20
>         *val =3D sign_extend32(be16_to_cpu(rawval),