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hwmon: (aquacomputer_d5next) Avoid truncating scaled sensor readings

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High Flow Next power is reported in watts. Multiplying the 16-bit value
by one million can overflow both the signed intermediate and the u32
cache. Store power in long, perform the conversion in u64, and clamp to
LONG_MAX. The other existing power conversions fit in a signed 32-bit
value. Return -ENODATA for unavailable power instead of exposing the
stored error as a reading.

The power cache is updated by HID reports without the hwmon read mutex.
Read it once with READ_ONCE() and use that snapshot for both the
availability check and the returned value. Mark the corresponding
updates with WRITE_ONCE() so that the shared accesses are explicit.

Widen the shared current cache to u32. The Aquastream XT conversion to
milliamperes can exceed 65535 mA; clamp its negative conversion results
to zero before assigning to the unsigned cache. This also permits devices
with scaled aggregate currents to store milliamperes directly.

Fixes: aed80bb91d ("hwmon: (aquacomputer_d5next) Add support for Aquacomputer High Flow Next")
Cc: stable@vger.kernel.org
Signed-off-by: Vas Zayarskiy <contact@vasily.cc>
Link: https://patch.msgid.link/20260927191316.4137752-2-contact@vasily.cc
[groeck: Dropped obsolete 'Assisted-by: tag]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Vas Zayarskiy 2026-09-27 22:13:12 +03:00 committed by Guenter Roeck
parent 1a30ea0be6
commit c221091f7e
1 changed files with 18 additions and 11 deletions
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29
drivers/hwmon/aquacomputer_d5next.c
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@ -19,6 +19,7 @@
#include <linux/hwmon.h>
#include <linux/jiffies.h>
#include <linux/ktime.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/unaligned.h>
@ -612,9 +613,9 @@ struct aqc_data {
u32 speed_input_min[1];
u32 speed_input_target[1];
u32 speed_input_max[1];
u32 power_input[8];
long power_input[8];
u16 voltage_input[8];
u16 current_input[8];
u32 current_input[8];
/* Label values */
const char *const *temp_label;
@ -989,7 +990,7 @@ static int aqc_legacy_read(struct aqc_data *priv)
/* Calculation derived from linear regression */
sensor_value = get_unaligned_le16(priv->buffer + AQUASTREAMXT_PUMP_CURR_OFFSET);
priv->current_input[0] = DIV_ROUND_CLOSEST(sensor_value * 176, 100) - 52;
priv->current_input[0] = max(DIV_ROUND_CLOSEST(sensor_value * 176, 100) - 52, 0);
sensor_value = get_unaligned_le16(priv->buffer + AQUASTREAMXT_PUMP_VOLTAGE_OFFSET);
priv->voltage_input[0] = DIV_ROUND_CLOSEST(sensor_value * 1000, 61);
@ -1019,6 +1020,7 @@ static int aqc_legacy_read(struct aqc_data *priv)
static int aqc_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long *val)
{
long power;
int ret;
struct aqc_data *priv = dev_get_drvdata(dev);
@ -1083,7 +1085,10 @@ static int aqc_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
}
break;
case hwmon_power:
*val = priv->power_input[channel];
power = READ_ONCE(priv->power_input[channel]);
if (power == -ENODATA)
return -ENODATA;
*val = power;
break;
case hwmon_pwm:
switch (priv->kind) {
@ -1383,9 +1388,9 @@ static int aqc_raw_event(struct hid_device *hdev, struct hid_report *report, u8
priv->speed_input[i] =
get_unaligned_be16(data + priv->fan_sensor_offsets[i] +
priv->fan_structure->speed);
priv->power_input[i] =
get_unaligned_be16(data + priv->fan_sensor_offsets[i] +
priv->fan_structure->power) * 10000;
WRITE_ONCE(priv->power_input[i],
get_unaligned_be16(data + priv->fan_sensor_offsets[i] +
priv->fan_structure->power) * 10000);
priv->voltage_input[i] =
get_unaligned_be16(data + priv->fan_sensor_offsets[i] +
priv->fan_structure->voltage) * 10;
@ -1425,7 +1430,8 @@ static int aqc_raw_event(struct hid_device *hdev, struct hid_report *report, u8
priv->speed_input[2] = get_unaligned_be16(data + AQUASTREAMULT_PRESSURE_OFFSET);
priv->speed_input[3] = get_unaligned_be16(data + AQUASTREAMULT_FLOW_SENSOR_OFFSET);
priv->power_input[1] = get_unaligned_be16(data + AQUASTREAMULT_PUMP_POWER) * 10000;
WRITE_ONCE(priv->power_input[1],
get_unaligned_be16(data + AQUASTREAMULT_PUMP_POWER) * 10000);
priv->voltage_input[1] = get_unaligned_be16(data + AQUASTREAMULT_PUMP_VOLTAGE) * 10;
@ -1438,10 +1444,11 @@ static int aqc_raw_event(struct hid_device *hdev, struct hid_report *report, u8
case highflownext:
/* If external temp sensor is not connected, its power reading is also N/A */
if (priv->temp_input[1] == -ENODATA)
priv->power_input[0] = -ENODATA;
WRITE_ONCE(priv->power_input[0], -ENODATA);
else
priv->power_input[0] =
get_unaligned_be16(data + HIGHFLOWNEXT_POWER) * 1000000;
WRITE_ONCE(priv->power_input[0],
min_t(u64, get_unaligned_be16(data + HIGHFLOWNEXT_POWER) *
1000000ULL, LONG_MAX));
priv->voltage_input[0] = get_unaligned_be16(data + HIGHFLOWNEXT_5V_VOLTAGE) * 10;
priv->voltage_input[1] =