[PATCH v3] iio: imu: kmx61: Use guard(mutex)() family over manual locking

[PATCH v3] iio: imu: kmx61: Use guard(mutex)() family over manual locking

[Maxwell Doose]

Include linux/cleanup.h to take advantage of new macros.

Replace manual mutex_lock() and mutex_unlock() calls across the file
with guard(mutex)() and scoped_guard() where appropriate. This will help
modernize the driver with up-to-date functions/macros.

Remove now redundant gotos and ret variables, as the new RAII macros
make them unneeded.

Signed-off-by: Maxwell Doose <m32285159@gmail.com>
---
 v2:
 - Remove redundant blank line per Andy.
 - Put kmx61_set_mode() function call in kmx61_runtime_suspend() on one
   line per Andy.

 v3:
 - Add dedicated scope for guards.

 drivers/iio/imu/kmx61.c | 82 +++++++++++++++--------------------------
 1 file changed, 29 insertions(+), 53 deletions(-)

 drivers/iio/imu/kmx61.c | 88 ++++++++++++++++-------------------------
 1 file changed, 33 insertions(+), 55 deletions(-)

diff --git a/drivers/iio/imu/kmx61.c b/drivers/iio/imu/kmx61.c
index 3cd91d8a89ee..a112e291c064 100644
--- a/drivers/iio/imu/kmx61.c
+++ b/drivers/iio/imu/kmx61.c
@@ -7,6 +7,7 @@
  * IIO driver for KMX61 (7-bit I2C slave address 0x0E or 0x0F).
  */
 
+#include <linux/cleanup.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/mod_devicetable.h>
@@ -783,7 +784,7 @@ static int kmx61_read_raw(struct iio_dev *indio_dev,
 	struct kmx61_data *data = kmx61_get_data(indio_dev);
 
 	switch (mask) {
-	case IIO_CHAN_INFO_RAW:
+	case IIO_CHAN_INFO_RAW: {
 		switch (chan->type) {
 		case IIO_ACCEL:
 			base_reg = KMX61_ACC_XOUT_L;
@@ -794,28 +795,24 @@ static int kmx61_read_raw(struct iio_dev *indio_dev,
 		default:
 			return -EINVAL;
 		}
-		mutex_lock(&data->lock);
+		guard(mutex)(&data->lock);
 
 		ret = kmx61_set_power_state(data, true, chan->address);
-		if (ret) {
-			mutex_unlock(&data->lock);
+		if (ret)
 			return ret;
-		}
 
 		ret = kmx61_read_measurement(data, base_reg, chan->scan_index);
 		if (ret < 0) {
 			kmx61_set_power_state(data, false, chan->address);
-			mutex_unlock(&data->lock);
 			return ret;
 		}
 		*val = sign_extend32(ret >> chan->scan_type.shift,
 				     chan->scan_type.realbits - 1);
 		ret = kmx61_set_power_state(data, false, chan->address);
-
-		mutex_unlock(&data->lock);
 		if (ret)
 			return ret;
 		return IIO_VAL_INT;
+	}
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_ACCEL:
@@ -830,17 +827,17 @@ static int kmx61_read_raw(struct iio_dev *indio_dev,
 		default:
 			return -EINVAL;
 		}
-	case IIO_CHAN_INFO_SAMP_FREQ:
+	case IIO_CHAN_INFO_SAMP_FREQ: {
 		if (chan->type != IIO_ACCEL && chan->type != IIO_MAGN)
 			return -EINVAL;
 
-		mutex_lock(&data->lock);
-		ret = kmx61_get_odr(data, val, val2, chan->address);
-		mutex_unlock(&data->lock);
+		scoped_guard(mutex, &data->lock)
+			ret = kmx61_get_odr(data, val, val2, chan->address);
 		if (ret)
 			return -EINVAL;
 		return IIO_VAL_INT_PLUS_MICRO;
 	}
+	}
 	return -EINVAL;
 }
 
@@ -852,26 +849,24 @@ static int kmx61_write_raw(struct iio_dev *indio_dev,
 	struct kmx61_data *data = kmx61_get_data(indio_dev);
 
 	switch (mask) {
-	case IIO_CHAN_INFO_SAMP_FREQ:
+	case IIO_CHAN_INFO_SAMP_FREQ: {
 		if (chan->type != IIO_ACCEL && chan->type != IIO_MAGN)
 			return -EINVAL;
 
-		mutex_lock(&data->lock);
-		ret = kmx61_set_odr(data, val, val2, chan->address);
-		mutex_unlock(&data->lock);
-		return ret;
-	case IIO_CHAN_INFO_SCALE:
+		guard(mutex)(&data->lock);
+		return kmx61_set_odr(data, val, val2, chan->address);
+	}
+	case IIO_CHAN_INFO_SCALE: {
 		switch (chan->type) {
 		case IIO_ACCEL:
 			if (val != 0)
 				return -EINVAL;
-			mutex_lock(&data->lock);
-			ret = kmx61_set_scale(data, val2);
-			mutex_unlock(&data->lock);
-			return ret;
+			guard(mutex)(&data->lock);
+			return kmx61_set_scale(data, val2);
 		default:
 			return -EINVAL;
 		}
+	}
 	default:
 		return -EINVAL;
 	}
@@ -945,28 +940,25 @@ static int kmx61_write_event_config(struct iio_dev *indio_dev,
 	if (state && data->ev_enable_state)
 		return 0;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 
 	if (!state && data->motion_trig_on) {
 		data->ev_enable_state = false;
-		goto err_unlock;
+		return ret;
 	}
 
 	ret = kmx61_set_power_state(data, state, KMX61_ACC);
 	if (ret < 0)
-		goto err_unlock;
+		return ret;
 
 	ret = kmx61_setup_any_motion_interrupt(data, state);
 	if (ret < 0) {
 		kmx61_set_power_state(data, false, KMX61_ACC);
-		goto err_unlock;
+		return ret;
 	}
 
 	data->ev_enable_state = state;
 
-err_unlock:
-	mutex_unlock(&data->lock);
-
 	return ret;
 }
 
@@ -1020,11 +1012,11 @@ static int kmx61_data_rdy_trigger_set_state(struct iio_trigger *trig,
 	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 	struct kmx61_data *data = kmx61_get_data(indio_dev);
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 
 	if (!state && data->ev_enable_state && data->motion_trig_on) {
 		data->motion_trig_on = false;
-		goto err_unlock;
+		return ret;
 	}
 
 	if (data->acc_dready_trig == trig || data->motion_trig == trig)
@@ -1034,7 +1026,7 @@ static int kmx61_data_rdy_trigger_set_state(struct iio_trigger *trig,
 
 	ret = kmx61_set_power_state(data, state, device);
 	if (ret < 0)
-		goto err_unlock;
+		return ret;
 
 	if (data->acc_dready_trig == trig || data->mag_dready_trig == trig)
 		ret = kmx61_setup_new_data_interrupt(data, state, device);
@@ -1042,7 +1034,7 @@ static int kmx61_data_rdy_trigger_set_state(struct iio_trigger *trig,
 		ret = kmx61_setup_any_motion_interrupt(data, state);
 	if (ret < 0) {
 		kmx61_set_power_state(data, false, device);
-		goto err_unlock;
+		return ret;
 	}
 
 	if (data->acc_dready_trig == trig)
@@ -1051,8 +1043,6 @@ static int kmx61_data_rdy_trigger_set_state(struct iio_trigger *trig,
 		data->mag_dready_trig_on = state;
 	else
 		data->motion_trig_on = state;
-err_unlock:
-	mutex_unlock(&data->lock);
 
 	return ret;
 }
@@ -1195,19 +1185,17 @@ static irqreturn_t kmx61_trigger_handler(int irq, void *p)
 	else
 		base = KMX61_MAG_XOUT_L;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	iio_for_each_active_channel(indio_dev, bit) {
 		ret = kmx61_read_measurement(data, base, bit);
 		if (ret < 0) {
-			mutex_unlock(&data->lock);
-			goto err;
+			iio_trigger_notify_done(indio_dev->trig);
+			return IRQ_HANDLED;
 		}
 		buffer[i++] = ret;
 	}
-	mutex_unlock(&data->lock);
 
 	iio_push_to_buffers(indio_dev, buffer);
-err:
 	iio_trigger_notify_done(indio_dev->trig);
 
 	return IRQ_HANDLED;
@@ -1419,22 +1407,16 @@ static void kmx61_remove(struct i2c_client *client)
 		iio_trigger_unregister(data->motion_trig);
 	}
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
-	mutex_unlock(&data->lock);
 }
 
 static int kmx61_suspend(struct device *dev)
 {
-	int ret;
 	struct kmx61_data *data = i2c_get_clientdata(to_i2c_client(dev));
 
-	mutex_lock(&data->lock);
-	ret = kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG,
-			     false);
-	mutex_unlock(&data->lock);
-
-	return ret;
+	guard(mutex)(&data->lock);
+	return kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, false);
 }
 
 static int kmx61_resume(struct device *dev)
@@ -1453,13 +1435,9 @@ static int kmx61_resume(struct device *dev)
 static int kmx61_runtime_suspend(struct device *dev)
 {
 	struct kmx61_data *data = i2c_get_clientdata(to_i2c_client(dev));
-	int ret;
 
-	mutex_lock(&data->lock);
-	ret = kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
-	mutex_unlock(&data->lock);
-
-	return ret;
+	guard(mutex)(&data->lock);
+	return kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
 }
 
 static int kmx61_runtime_resume(struct device *dev)
-- 
2.54.0

Re: [PATCH v3] iio: imu: kmx61: Use guard(mutex)() family over manual locking

[Andy Shevchenko]

On Tue, May 05, 2026 at 07:47:06AM -0500, Maxwell Doose wrote:
> Include linux/cleanup.h to take advantage of new macros.
> 
> Replace manual mutex_lock() and mutex_unlock() calls across the file
> with guard(mutex)() and scoped_guard() where appropriate. This will help
> modernize the driver with up-to-date functions/macros.
> 
> Remove now redundant gotos and ret variables, as the new RAII macros
> make them unneeded.

Did you compile this version?

...

> -	case IIO_CHAN_INFO_SAMP_FREQ:
> +	case IIO_CHAN_INFO_SAMP_FREQ: {
>  		if (chan->type != IIO_ACCEL && chan->type != IIO_MAGN)
>  			return -EINVAL;
>  
> -		mutex_lock(&data->lock);
> -		ret = kmx61_get_odr(data, val, val2, chan->address);
> -		mutex_unlock(&data->lock);
> +		scoped_guard(mutex, &data->lock)
> +			ret = kmx61_get_odr(data, val, val2, chan->address);
>  		if (ret)
>  			return -EINVAL;
>  		return IIO_VAL_INT_PLUS_MICRO;
>  	}
> +	}

This looks suspicious.

...

Please, slow down and check the patches you sent.

Also, use, if not yet, --histogram when preparing patches, it might make them
more readable.

...

>  	switch (mask) {
> -	case IIO_CHAN_INFO_SAMP_FREQ:
> +	case IIO_CHAN_INFO_SAMP_FREQ: {
>  		if (chan->type != IIO_ACCEL && chan->type != IIO_MAGN)
>  			return -EINVAL;
>  
> -		mutex_lock(&data->lock);
> -		ret = kmx61_set_odr(data, val, val2, chan->address);
> -		mutex_unlock(&data->lock);
> -		return ret;
> -	case IIO_CHAN_INFO_SCALE:
> +		guard(mutex)(&data->lock);

+ blank line.

> +		return kmx61_set_odr(data, val, val2, chan->address);
> +	}
> +	case IIO_CHAN_INFO_SCALE: {
>  		switch (chan->type) {
>  		case IIO_ACCEL:
>  			if (val != 0)
>  				return -EINVAL;
> -			mutex_lock(&data->lock);
> -			ret = kmx61_set_scale(data, val2);
> -			mutex_unlock(&data->lock);
> -			return ret;
> +			guard(mutex)(&data->lock);
> +			return kmx61_set_scale(data, val2);

Missing scope.

>  		default:
>  			return -EINVAL;
>  		}
> +	}
>  	default:
>  		return -EINVAL;
>  	}

...

> -	mutex_lock(&data->lock);
> +	guard(mutex)(&data->lock);

+ blank line.

>  	iio_for_each_active_channel(indio_dev, bit) {
>  		ret = kmx61_read_measurement(data, base, bit);
>  		if (ret < 0) {
> -			mutex_unlock(&data->lock);
> -			goto err;
> +			iio_trigger_notify_done(indio_dev->trig);
> +			return IRQ_HANDLED;
>  		}
>  		buffer[i++] = ret;
>  	}
> -	mutex_unlock(&data->lock);
>  
>  	iio_push_to_buffers(indio_dev, buffer);
> -err:
>  	iio_trigger_notify_done(indio_dev->trig);
>  
>  	return IRQ_HANDLED;

...


> -	mutex_lock(&data->lock);
> +	guard(mutex)(&data->lock);

+ blank line.

>  	kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
> -	mutex_unlock(&data->lock);

Since guard()() is not like lock/unlock, the blank line is better for
readability. lock/unlock scenarios look&feel as special scope, that's why
the blank lines there are optional.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v3] iio: imu: kmx61: Use guard(mutex)() family over manual locking

[Maxwell Doose]

On Tue, May 5, 2026 at 8:08 AM Andy Shevchenko
<andriy.shevchenko@intel.com> wrote:
>
> On Tue, May 05, 2026 at 07:47:06AM -0500, Maxwell Doose wrote:
> > Include linux/cleanup.h to take advantage of new macros.
> >
> > Replace manual mutex_lock() and mutex_unlock() calls across the file
> > with guard(mutex)() and scoped_guard() where appropriate. This will help
> > modernize the driver with up-to-date functions/macros.
> >
> > Remove now redundant gotos and ret variables, as the new RAII macros
> > make them unneeded.
>
> Did you compile this version?
>
> ...
>
> > -     case IIO_CHAN_INFO_SAMP_FREQ:
> > +     case IIO_CHAN_INFO_SAMP_FREQ: {
> >               if (chan->type != IIO_ACCEL && chan->type != IIO_MAGN)
> >                       return -EINVAL;
> >
> > -             mutex_lock(&data->lock);
> > -             ret = kmx61_get_odr(data, val, val2, chan->address);
> > -             mutex_unlock(&data->lock);
> > +             scoped_guard(mutex, &data->lock)
> > +                     ret = kmx61_get_odr(data, val, val2, chan->address);
> >               if (ret)
> >                       return -EINVAL;
> >               return IIO_VAL_INT_PLUS_MICRO;
> >       }
> > +     }
>
> This looks suspicious.
>
> ...
>
> Please, slow down and check the patches you sent.
>
> Also, use, if not yet, --histogram when preparing patches, it might make them
> more readable.
>

Thanks for the tip.

>
[snip]
>
> Since guard()() is not like lock/unlock, the blank line is better for
> readability. lock/unlock scenarios look&feel as special scope, that's why
> the blank lines there are optional.
>


Sorry, I was in a rush this morning and I wanted to keep to my promise
of getting it out this morning. I can make a v4 but I currently don't
have time unfortunately, so it'll have to wait.

best regards,
max