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hwmon: (pmbus/core) mutex_lock write in pmbus_set_samples 

update_lock is a mutex intended to protect write operations. It was not
taken, however, when _pmbus_write_word_data is called from
pmbus_set_samples() function which may cause problems especially when
some PMBUS_VIRT_* operation is implemented as a read-modify-write cycle.

This patch makes sure the lock is held during the operation.

Fixes: 49c4455dcc ("hwmon: (pmbus) Introduce PMBUS_VIRT_*_SAMPLES registers")
Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
[groeck: Declared and initialized missing 'data' variable]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Adamski, Krzysztof (Nokia - PL/Wroclaw) 2019-05-29 14:33:52 +00:00 committed by Guenter Roeck
parent c41dd48e21
commit 38463721ec
1 changed files with 3 additions and 0 deletions
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3
drivers/hwmon/pmbus/pmbus_core.c
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@ -1942,11 +1942,14 @@ static ssize_t pmbus_set_samples(struct device *dev,
long val;
struct i2c_client *client = to_i2c_client(dev->parent);
struct pmbus_samples_reg *reg = to_samples_reg(devattr);
struct pmbus_data *data = i2c_get_clientdata(client);
if (kstrtol(buf, 0, &val) < 0)
return -EINVAL;
mutex_lock(&data->update_lock);
ret = _pmbus_write_word_data(client, reg->page, reg->attr->reg, val);
mutex_unlock(&data->update_lock);
return ret ? : count;
}