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    Subject[PATCH v2] iio: adc: exynos_adc: Replace indio_dev->mlock with own device lock
    Date
    From: Sergiu Cuciurean <sergiu.cuciurean@analog.com>

    As part of the general cleanup of indio_dev->mlock, this change replaces
    it with a local lock, to protect potential concurrent access to the
    completion callback during a conversion.

    This is part of a bigger cleanup.
    Link: https://lore.kernel.org/linux-iio/CA+U=Dsoo6YABe5ODLp+eFNPGFDjk5ZeQEceGkqjxXcVEhLWubw@mail.gmail.com/

    Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
    Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
    Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
    ---
    drivers/iio/adc/exynos_adc.c | 20 ++++++++++++++++----
    1 file changed, 16 insertions(+), 4 deletions(-)

    diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
    index 20477b249f2a..99f4404e9fd1 100644
    --- a/drivers/iio/adc/exynos_adc.c
    +++ b/drivers/iio/adc/exynos_adc.c
    @@ -138,6 +138,16 @@ struct exynos_adc {
    bool read_ts;
    u32 ts_x;
    u32 ts_y;
    +
    + /*
    + * Lock to protect from potential concurrent access to the
    + * completion callback during a manual conversion. For this driver
    + * a wait-callback is used to wait for the conversion result,
    + * so in the meantime no other read request (or conversion start)
    + * must be performed, otherwise it would interfere with the
    + * current conversion result.
    + */
    + struct mutex lock;
    };

    struct exynos_adc_data {
    @@ -542,7 +552,7 @@ static int exynos_read_raw(struct iio_dev *indio_dev,
    return -EINVAL;
    }

    - mutex_lock(&indio_dev->mlock);
    + mutex_lock(&info->lock);
    reinit_completion(&info->completion);

    /* Select the channel to be used and Trigger conversion */
    @@ -562,7 +572,7 @@ static int exynos_read_raw(struct iio_dev *indio_dev,
    ret = IIO_VAL_INT;
    }

    - mutex_unlock(&indio_dev->mlock);
    + mutex_unlock(&info->lock);

    return ret;
    }
    @@ -573,7 +583,7 @@ static int exynos_read_s3c64xx_ts(struct iio_dev *indio_dev, int *x, int *y)
    unsigned long timeout;
    int ret;

    - mutex_lock(&indio_dev->mlock);
    + mutex_lock(&info->lock);
    info->read_ts = true;

    reinit_completion(&info->completion);
    @@ -598,7 +608,7 @@ static int exynos_read_s3c64xx_ts(struct iio_dev *indio_dev, int *x, int *y)
    }

    info->read_ts = false;
    - mutex_unlock(&indio_dev->mlock);
    + mutex_unlock(&info->lock);

    return ret;
    }
    @@ -868,6 +878,8 @@ static int exynos_adc_probe(struct platform_device *pdev)
    indio_dev->channels = exynos_adc_iio_channels;
    indio_dev->num_channels = info->data->num_channels;

    + mutex_init(&info->lock);
    +
    ret = request_irq(info->irq, exynos_adc_isr,
    0, dev_name(&pdev->dev), info);
    if (ret < 0) {
    --
    2.17.1
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