On Mon, 13 Jun 2022 12:11:09 +0200 Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
From: Miquel Raynal miquel.raynal@bootlin.com
[ Upstream commit 474010127e2505fc463236470908e1ff5ddb3578 ]
Right now the (framework) mlock lock is (ab)used for multiple purposes: 1- protecting concurrent accesses over the odr local cache 2- avoid changing samplig frequency whilst buffer is running
Let's start by handling situation #1 with a local lock.
This is harmless, but not a fix but rather part of a long running effort to abstract away the use of iio_dev->mlock.
What's there before this isn't broken, but rather isn't the way we would do it today.
Thanks,
Jonathan
Suggested-by: Jonathan Cameron jic23@kernel.org Cc: Denis Ciocca denis.ciocca@st.com Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com Link: https://lore.kernel.org/r/20220207143840.707510-7-miquel.raynal@bootlin.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org
.../iio/common/st_sensors/st_sensors_core.c | 24 ++++++++++++++----- include/linux/iio/common/st_sensors.h | 3 +++ 2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c index 0bbb090b108c..aff981551617 100644 --- a/drivers/iio/common/st_sensors/st_sensors_core.c +++ b/drivers/iio/common/st_sensors/st_sensors_core.c @@ -71,16 +71,18 @@ static int st_sensors_match_odr(struct st_sensor_settings *sensor_settings, int st_sensors_set_odr(struct iio_dev *indio_dev, unsigned int odr) {
- int err;
- int err = 0; struct st_sensor_odr_avl odr_out = {0, 0}; struct st_sensor_data *sdata = iio_priv(indio_dev);
- mutex_lock(&sdata->odr_lock);
- if (!sdata->sensor_settings->odr.mask)
return 0;
goto unlock_mutex;err = st_sensors_match_odr(sdata->sensor_settings, odr, &odr_out); if (err < 0)
goto st_sensors_match_odr_error;
goto unlock_mutex;if ((sdata->sensor_settings->odr.addr == sdata->sensor_settings->pw.addr) && @@ -103,7 +105,9 @@ int st_sensors_set_odr(struct iio_dev *indio_dev, unsigned int odr) if (err >= 0) sdata->odr = odr_out.hz; -st_sensors_match_odr_error: +unlock_mutex:
- mutex_unlock(&sdata->odr_lock);
- return err;
} EXPORT_SYMBOL(st_sensors_set_odr); @@ -365,6 +369,8 @@ int st_sensors_init_sensor(struct iio_dev *indio_dev, struct st_sensors_platform_data *of_pdata; int err = 0;
- mutex_init(&sdata->odr_lock);
- /* If OF/DT pdata exists, it will take precedence of anything else */ of_pdata = st_sensors_dev_probe(indio_dev->dev.parent, pdata); if (IS_ERR(of_pdata))
@@ -558,18 +564,24 @@ int st_sensors_read_info_raw(struct iio_dev *indio_dev, err = -EBUSY; goto out; } else {
mutex_lock(&sdata->odr_lock);
if (err < 0)
if (err < 0) {mutex_unlock(&sdata->odr_lock); goto out;}msleep((sdata->sensor_settings->bootime * 1000) / sdata->odr); err = st_sensors_read_axis_data(indio_dev, ch, val);
if (err < 0)
if (err < 0) {mutex_unlock(&sdata->odr_lock); goto out;}*val = *val >> ch->scan_type.shift; err = st_sensors_set_enable(indio_dev, false);
mutex_unlock(&sdata->odr_lock);out: mutex_unlock(&indio_dev->mlock); diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h index 8bdbaf3f3796..69f4a1f6b536 100644 --- a/include/linux/iio/common/st_sensors.h +++ b/include/linux/iio/common/st_sensors.h @@ -238,6 +238,7 @@ struct st_sensor_settings {
- @hw_irq_trigger: if we're using the hardware interrupt on the sensor.
- @hw_timestamp: Latest timestamp from the interrupt handler, when in use.
- @buffer_data: Data used by buffer part.
*/
- @odr_lock: Local lock for preventing concurrent ODR accesses/changes
struct st_sensor_data { struct device *dev; @@ -263,6 +264,8 @@ struct st_sensor_data { s64 hw_timestamp; char buffer_data[ST_SENSORS_MAX_BUFFER_SIZE] ____cacheline_aligned;
- struct mutex odr_lock;
}; #ifdef CONFIG_IIO_BUFFER