Re: [PATCH v2] iio: imu: bmi160: add mutex_lock for avoiding race

[Guoqing Chi <chi962464zy@163.com>]

On Sat, 23 Jan 2021 15:26:59 +0000
Jonathan Cameron <jic23@kernel.org> wrote:

> On Wed, 20 Jan 2021 07:06:23 -0800
> Tom Rix <trix@redhat.com> wrote:
> 
> > On 1/19/21 5:48 PM, Guoqing Chi wrote:  
> > > On Tue, 19 Jan 2021 06:54:45 -0800
> > > Tom Rix <trix@redhat.com> wrote:
> > >    
> > >> On 1/19/21 3:22 AM, Guoqing Chi wrote:    
> > >>> From: chiguoqing <chi962464zy@163.com>
> > >>>
> > >>> Adding mutex_lock, when read and write reg need to use this
> > >>> lock to avoid race.
> > >>>
> > >>> Signed-off-by: Guoqing Chi <chiguoqing@yulong.com>
> > >>> ---
> > >>> v2:Follow write function to fix read function.
> > >>> Adding mutex init in core probe function.
> > >>> Adding break in switch case at read and write function.
> > >>>
> > >>>  drivers/iio/imu/bmi160/bmi160.h      |  2 ++
> > >>>  drivers/iio/imu/bmi160/bmi160_core.c | 34
> > >>> +++++++++++++++++++--------- 2 files changed, 25 insertions(+),
> > >>> 11 deletions(-)
> > >>>
> > >>> diff --git a/drivers/iio/imu/bmi160/bmi160.h
> > >>> b/drivers/iio/imu/bmi160/bmi160.h index
> > >>> 32c2ea2d7112..0c189a8b5b53 100644 ---
> > >>> a/drivers/iio/imu/bmi160/bmi160.h +++
> > >>> b/drivers/iio/imu/bmi160/bmi160.h @@ -3,9 +3,11 @@
> > >>>  #define BMI160_H_
> > >>>  
> > >>>  #include <linux/iio/iio.h>
> > >>> +#include <linux/mutex.h>
> > >>>  #include <linux/regulator/consumer.h>
> > >>>  
> > >>>  struct bmi160_data {
> > >>> +	struct mutex lock;
> > >>>  	struct regmap *regmap;
> > >>>  	struct iio_trigger *trig;
> > >>>  	struct regulator_bulk_data supplies[2];
> > >>> diff --git a/drivers/iio/imu/bmi160/bmi160_core.c
> > >>> b/drivers/iio/imu/bmi160/bmi160_core.c index
> > >>> 290b5ef83f77..e303378f4841 100644 ---
> > >>> a/drivers/iio/imu/bmi160/bmi160_core.c +++
> > >>> b/drivers/iio/imu/bmi160/bmi160_core.c @@ -452,26 +452,32 @@
> > >>> static int bmi160_read_raw(struct iio_dev *indio_dev, int ret;
> > >>>  	struct bmi160_data *data = iio_priv(indio_dev);
> > >>>  
> > >>> +	mutex_lock(&data->lock);
> > >>>  	switch (mask) {
> > >>>  	case IIO_CHAN_INFO_RAW:
> > >>>  		ret = bmi160_get_data(data, chan->type,
> > >>> chan->channel2, val);
> > >>> -		if (ret)
> > >>> -			return ret;
> > >>> -		return IIO_VAL_INT;
> > >>> +		if (!ret)
> > >>> +			ret = IIO_VAL_INT;
> > >>> +		break;
> > >>>  	case IIO_CHAN_INFO_SCALE:
> > >>>  		*val = 0;
> > >>>  		ret = bmi160_get_scale(data,
> > >>>  				       bmi160_to_sensor(chan->type),
> > >>> val2);
> > >>> -		return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
> > >>> +		if (!ret)
> > >>> +			ret = IIO_VAL_INT_PLUS_MICRO;      
> > >> Looking better, another question..
> > >>
> > >> Why does the write() function return the results directly while
> > >> the read() function
> > >>
> > >> translates them to other values ?
> > >>
> > >> Tom    
> > > It is original design in this driver. In order to
> > > differentiate raw to scale and SAMP_FREQ, while the scale and
> > > SAMP_FREQ are needless. I think log information can be added for
> > > this purpose, and return results directly.
> > > It is not change the return values for my modify.It's best to
> > > keep the original design.Is that all right?    
> > 
> > Ok.
> > 
> > Reviewed-by: Tom Rix <trix@redhat.com>  
> 
> Hi Guoqing Chi,
> 
> For some reason the original patch email (start of this thread) never
> made it to my inbox or indeed the archive at lore.kernel.org.
> 
> Please resend (picking up Tom's reviewed by) and make sure to cc
> linux-iio@vger.kernel.org + jic23@kernel.org
> 
> Then check if they make it to lore.kernel.org as that should highlight
> any issues where it is getting blocked etc.
> 
> Thanks,
> 
> Jonathan

Hi Jonathan,

I have resend patch V2(picking up Tom's reviewed by) for add
linux-iio@vger.kernel.org + jic23@kernel.org.

Thanks.

> 
> >   
> > > Guoqing Chi    
> > >>> +		break;
> > >>>  	case IIO_CHAN_INFO_SAMP_FREQ:
> > >>>  		ret = bmi160_get_odr(data,
> > >>> bmi160_to_sensor(chan->type), val, val2);
> > >>> -		return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
> > >>> +		if (!ret)
> > >>> +			ret = IIO_VAL_INT_PLUS_MICRO;
> > >>> +		break;
> > >>>  	default:
> > >>> -		return -EINVAL;
> > >>> +		ret = -EINVAL;
> > >>>  	}
> > >>> +	mutex_unlock(&data->lock);
> > >>>  
> > >>> -	return 0;
> > >>> +	return ret;
> > >>>  }
> > >>>  
> > >>>  static int bmi160_write_raw(struct iio_dev *indio_dev,
> > >>> @@ -479,19 +485,24 @@ static int bmi160_write_raw(struct iio_dev
> > >>> *indio_dev, int val, int val2, long mask)
> > >>>  {
> > >>>  	struct bmi160_data *data = iio_priv(indio_dev);
> > >>> +	int result;
> > >>>  
> > >>> +	mutex_lock(&data->lock);
> > >>>  	switch (mask) {
> > >>>  	case IIO_CHAN_INFO_SCALE:
> > >>> -		return bmi160_set_scale(data,
> > >>> +		result = bmi160_set_scale(data,
> > >>>  					bmi160_to_sensor(chan->type),
> > >>> val2);
> > >>> +		break;
> > >>>  	case IIO_CHAN_INFO_SAMP_FREQ:
> > >>> -		return bmi160_set_odr(data,
> > >>> bmi160_to_sensor(chan->type),
> > >>> +		result = bmi160_set_odr(data,
> > >>> bmi160_to_sensor(chan->type), val, val2);
> > >>> +		break;
> > >>>  	default:
> > >>> -		return -EINVAL;
> > >>> +		result = -EINVAL;
> > >>>  	}
> > >>> +	mutex_unlock(&data->lock);
> > >>>  
> > >>> -	return 0;
> > >>> +	return result;
> > >>>  }
> > >>>  
> > >>>  static
> > >>> @@ -838,6 +849,7 @@ int bmi160_core_probe(struct device *dev,
> > >>> struct regmap *regmap, return -ENOMEM;
> > >>>  
> > >>>  	data = iio_priv(indio_dev);
> > >>> +	mutex_init(&data->lock);
> > >>>  	dev_set_drvdata(dev, indio_dev);
> > >>>  	data->regmap = regmap;
> > >>>        
> >