* [PATCH v2 resend] iio: imu: bmi160: add mutex_lock for avoiding race
@ 2021-01-25 1:53 Guoqing Chi
[not found] ` <20210131112143.200cf70a@archlinux>
0 siblings, 1 reply; 2+ messages in thread
From: Guoqing Chi @ 2021-01-25 1:53 UTC (permalink / raw)
To: trix
Cc: linux-iio, jic23, huyue2, linux-kernel, zhangwen, chiguoqing, chiguoqing
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>
Reviewed-by: Tom Rix <trix@redhat.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;
+ 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;
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread[parent not found: <20210131112143.200cf70a@archlinux>]
* Re: [PATCH v2 resend] iio: imu: bmi160: add mutex_lock for avoiding race [not found] ` <20210131112143.200cf70a@archlinux> @ 2021-02-01 1:15 ` Guoqing Chi 0 siblings, 0 replies; 2+ messages in thread From: Guoqing Chi @ 2021-02-01 1:15 UTC (permalink / raw) To: Jonathan Cameron Cc: trix, linux-iio, huyue2, linux-kernel, zhangwen, chiguoqing On Sun, 31 Jan 2021 11:21:43 +0000 Jonathan Cameron <jic23@kernel.org> wrote: > On Mon, 25 Jan 2021 09:53:44 +0800 > Guoqing Chi <chi962464zy@163.com> 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> > > Reviewed-by: Tom Rix <trix@redhat.com> > > Hi. Looking at this again, I'm not entirely sure I understand what > the race is. Could you give any example? > > Individual regmap accesses have their own internal protections > against races. We don't have an read modify write cycles that > I can see here, so I don't think there are any races. > > On another note however, there is a regmap_bulk_read into > a variable on the stack which is a problem for spi. Unlike i2c > the spi patch in regmap for bulk_reads can be zero copy which > means that the variable on the stack can be dma'd into. That's > a potential issue for some systems in which you can end up wiping > out whatever else gets changed in the same cacheline. > > To fix that, the variable should be in it's own cacheline. Either > do that by using kmalloc etc to put it on the stack, or add a > suitable buffer to priv, marked ___cacheline_aligned. Though once > you do that you will need locks to protect it as you've done > here. > > Jonathan Hi Jonathan It's my mistake. The regmap_bulk_read func has their own lock. So maybe we can give up my patch. Thanks. > > > > > --- > > 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; > > + 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; > > ^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-01-25 1:53 [PATCH v2 resend] iio: imu: bmi160: add mutex_lock for avoiding race Guoqing Chi
[not found] ` <20210131112143.200cf70a@archlinux>
2021-02-01 1:15 ` Guoqing Chi
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