[PATCH 6/7] iio: light: tsl2583: add locking to sysfs *_store() functions

[Brian Masney]

The sysfs attributes modifies variables that are accessed elsewhere when
a mutex is locked. Add locking to the sysfs *_store() functions to avoid
a possible race condition when measurements are taken.

Signed-off-by: Brian Masney <masn...@onstation.org>
---
 drivers/staging/iio/light/tsl2583.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/iio/light/tsl2583.c 
b/drivers/staging/iio/light/tsl2583.c
index 60f0ce9..47656ae 100644
--- a/drivers/staging/iio/light/tsl2583.c
+++ b/drivers/staging/iio/light/tsl2583.c
@@ -515,16 +515,21 @@ static ssize_t power_state_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, ret;
 
        if (kstrtoint(buf, 0, &value))
                return -EINVAL;
 
+       mutex_lock(&chip->als_mutex);
+
        if (!value)
                ret = taos_chip_off(indio_dev);
        else
                ret = taos_chip_on(indio_dev);
 
+       mutex_unlock(&chip->als_mutex);
+
        if (ret < 0)
                return ret;
 
@@ -568,6 +573,8 @@ static ssize_t illuminance0_calibscale_store(struct device 
*dev,
        if (kstrtoint(buf, 0, &value))
                goto gain_store_done;
 
+       mutex_lock(&chip->als_mutex);
+
        switch (value) {
        case 1:
                chip->taos_settings.als_gain = 0;
@@ -583,10 +590,12 @@ static ssize_t illuminance0_calibscale_store(struct 
device *dev,
                break;
        default:
                dev_err(dev, "Invalid Gain Index (must be 1,8,16,111)\n");
-               goto gain_store_done;
+               goto gain_store_unlock;
        }
        ret = len;
 
+gain_store_unlock:
+       mutex_unlock(&chip->als_mutex);
 gain_store_done:
        return ret;
 }
@@ -625,7 +634,9 @@ static ssize_t illuminance0_integration_time_store(struct 
device *dev,
        if (value % 50)
                goto als_time_store_done;
 
+       mutex_lock(&chip->als_mutex);
        chip->taos_settings.als_time = value;
+       mutex_unlock(&chip->als_mutex);
        ret = len;
 
 als_time_store_done:
@@ -663,7 +674,9 @@ static ssize_t illuminance0_calibbias_store(struct device 
*dev,
        else if (!value)
                return -EINVAL;
 
+       mutex_lock(&chip->als_mutex);
        chip->taos_settings.als_gain_trim = value;
+       mutex_unlock(&chip->als_mutex);
 
        return len;
 }
@@ -691,7 +704,9 @@ static ssize_t illuminance0_input_target_store(struct 
device *dev,
        else if (!value)
                return -EINVAL;
 
+       mutex_lock(&chip->als_mutex);
        chip->taos_settings.als_cal_target = value;
+       mutex_unlock(&chip->als_mutex);
 
        return len;
 }
@@ -714,6 +729,7 @@ static ssize_t illuminance0_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))
@@ -721,7 +737,9 @@ static ssize_t illuminance0_calibrate_store(struct device 
*dev,
        else if (value != 1)
                return -EINVAL;
 
+       mutex_lock(&chip->als_mutex);
        taos_als_calibrate(indio_dev);
+       mutex_unlock(&chip->als_mutex);
 
        return len;
 }
@@ -778,6 +796,8 @@ static ssize_t illuminance0_lux_table_store(struct device 
*dev,
                goto luxable_store_done;
        }
 
+       mutex_lock(&chip->als_mutex);
+
        if (chip->taos_chip_status == TSL258X_CHIP_WORKING) {
                ret = taos_chip_off(indio_dev);
                if (ret < 0)
@@ -794,6 +814,8 @@ static ssize_t illuminance0_lux_table_store(struct device 
*dev,
 
        ret = len;
 
+       mutex_unlock(&chip->als_mutex);
+
 luxable_store_done:
        return ret;
 }
-- 
2.7.4

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