From 38463721ec3c39acdabed3a89016ce6bb32a7543 Mon Sep 17 00:00:00 2001
From: "Adamski, Krzysztof (Nokia - PL/Wroclaw)" <krzysztof.adamski@nokia.com>
Date: Wed, 29 May 2019 14:33:52 +0000
Subject: [PATCH] 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: 49c4455dccf2 ("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>
---
drivers/hwmon/pmbus/pmbus_core.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index ef7ee90ee785d..48c2d5ae42a6f 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -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;
}
--
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