Hello Guenter Roeck,
Commit ec408845bc0f ("hwmon: (nct7802) Use multi-byte regmap
operations") from Jul 9, 2024 (linux-next), leads to the following
Smatch static checker warning:
drivers/hwmon/nct7802.c:411 in_alarm_show()
error: double locked '&data->access_lock' (orig line 406)
drivers/hwmon/nct7802.c
375 static ssize_t in_alarm_show(struct device *dev, struct device_attribute *attr,
376 char *buf)
377 {
378 struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
379 struct nct7802_data *data = dev_get_drvdata(dev);
380 int volt, min, max, ret;
381 unsigned int val;
382
383 mutex_lock(&data->in_alarm_lock);
384
385 /*
386 * The SMI Voltage status register is the only register giving a status
387 * for voltages. A bit is set for each input crossing a threshold, in
388 * both direction, but the "inside" or "outside" limits info is not
389 * available. Also this register is cleared on read.
390 * Note: this is not explicitly spelled out in the datasheet, but
391 * from experiment.
392 * To deal with this we use a status cache with one validity bit and
393 * one status bit for each input. Validity is cleared at startup and
394 * each time the register reports a change, and the status is processed
395 * by software based on current input value and limits.
396 */
397 ret = regmap_read(data->regmap, 0x1e, &val); /* SMI Voltage status */
398 if (ret < 0)
399 goto abort;
400
401 /* invalidate cached status for all inputs crossing a threshold */
402 data->in_status &= ~((val & 0x0f) << 4);
403
404 /* if cached status for requested input is invalid, update it */
405 if (!(data->in_status & (0x10 << sattr->index))) {
406 ret = nct7802_read_voltage(data, sattr->nr, 0);
I believe that the mutex_lock(&data->access_lock); in nct7802_read_voltage()
was supposed to be deleted.
407 if (ret < 0)
408 goto abort;
409 volt = ret;
410
--> 411 ret = nct7802_read_voltage(data, sattr->nr, 1);
412 if (ret < 0)
413 goto abort;
414 min = ret;
regards,
dan carpenter
