linux-kernel - Re: [PATCH 10/10] staging: iio: tsl2583: add locking to sysfs attributes

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Date:   Sun, 30 Oct 2016 18:43:23 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Brian Masney <masneyb@...tation.org>, linux-iio@...r.kernel.org
Cc:     devel@...verdev.osuosl.org, gregkh@...uxfoundation.org,
        lars@...afoo.de, pmeerw@...erw.net, knaack.h@....de,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        robh+dt@...nel.org, Mark.Rutland@....com
Subject: Re: [PATCH 10/10] staging: iio: tsl2583: add locking to sysfs
 attributes

On 28/10/16 11:00, Brian Masney wrote:
> in_illuminance_input_target_show(), in_illuminance_input_target_store(),
> in_illuminance_calibrate_store(), and in_illuminance_lux_table_store()
> accesses data from the tsl2583_chip struct. Some of these fields can be
> modified by other parts of the driver concurrently. This patch adds the
> mutex locking to these sysfs attributes.
> 
> Signed-off-by: Brian Masney <masneyb@...tation.org>
Applied to the togreg branch of iio.git and pushed out as testing for the
autobuilders to play with it.

Some elements of this were probably a little over paranoid but in theory
you might get a wrong reading (compared to what the hardware is set to) so
fair enough.

Good patch set.

Thanks,

Jonathan
> ---
>  drivers/staging/iio/light/tsl2583.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/iio/light/tsl2583.c b/drivers/staging/iio/light/tsl2583.c
> index 98afa5b..49b19f5 100644
> --- a/drivers/staging/iio/light/tsl2583.c
> +++ b/drivers/staging/iio/light/tsl2583.c
> @@ -513,8 +513,13 @@ static ssize_t in_illuminance_input_target_show(struct device *dev,
>  {
>  	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>  	struct tsl2583_chip *chip = iio_priv(indio_dev);
> +	int ret;
> +
> +	mutex_lock(&chip->als_mutex);
> +	ret = sprintf(buf, "%d\n", chip->taos_settings.als_cal_target);
> +	mutex_unlock(&chip->als_mutex);
>  
> -	return sprintf(buf, "%d\n", chip->taos_settings.als_cal_target);
> +	return ret;
>  }
>  
>  static ssize_t in_illuminance_input_target_store(struct device *dev,
> @@ -528,7 +533,9 @@ static ssize_t in_illuminance_input_target_store(struct device *dev,
>  	if (kstrtoint(buf, 0, &value) || !value)
>  		return -EINVAL;
>  
> +	mutex_lock(&chip->als_mutex);
>  	chip->taos_settings.als_cal_target = value;
> +	mutex_unlock(&chip->als_mutex);
>  
>  	return len;
>  }
> @@ -538,12 +545,15 @@ static ssize_t in_illuminance_calibrate_store(struct device *dev,
>  					      const char *buf, size_t len)
>  {
>  	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct tsl2583_chip *chip = iio_priv(indio_dev);
>  	int value;
>  
>  	if (kstrtoint(buf, 0, &value) || value != 1)
>  		return -EINVAL;
>  
> +	mutex_lock(&chip->als_mutex);
>  	taos_als_calibrate(indio_dev);
> +	mutex_unlock(&chip->als_mutex);
>  
>  	return len;
>  }
> @@ -583,6 +593,8 @@ static ssize_t in_illuminance_lux_table_store(struct device *dev,
>  	int value[ARRAY_SIZE(taos_device_lux) * 3 + 1];
>  	int n, ret = -EINVAL;
>  
> +	mutex_lock(&chip->als_mutex);
> +
>  	get_options(buf, ARRAY_SIZE(value), value);
>  
>  	/* We now have an array of ints starting at value[1], and
> @@ -617,6 +629,8 @@ static ssize_t in_illuminance_lux_table_store(struct device *dev,
>  	ret = len;
>  
>  done:
> +	mutex_unlock(&chip->als_mutex);
> +
>  	return ret;
>  }
>  
>