Am 14.12.2014 um 13:31 schrieb Hartmut Knaack: > Richard Weinberger schrieb am 03.12.2014 um 00:32: >> Make sure that the read function is not interrupted... > There is already a mutex iio_dev->info_exist_lock used to serialize > iio_channel_read(), which in turn accesses _read_raw(). See [1]. > > [1]http://lxr.free-electrons.com/ident?i=iio_channel_read
This is only for the in-kernel API and not for sysfs access. I.e. if you access via sysfs it is not protected. Thanks, //richard >> Signed-off-by: Richard Weinberger <[email protected]> >> --- >> drivers/iio/humidity/dht11.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c >> index d8771f5..168ebc4 100644 >> --- a/drivers/iio/humidity/dht11.c >> +++ b/drivers/iio/humidity/dht11.c >> @@ -29,6 +29,7 @@ >> #include <linux/wait.h> >> #include <linux/bitops.h> >> #include <linux/completion.h> >> +#include <linux/mutex.h> >> #include <linux/delay.h> >> #include <linux/gpio.h> >> #include <linux/of_gpio.h> >> @@ -57,6 +58,7 @@ struct dht11 { >> int irq; >> >> struct completion completion; >> + struct mutex lock; >> >> s64 timestamp; >> int temperature; >> @@ -145,6 +147,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev, >> struct dht11 *dht11 = iio_priv(iio_dev); >> int ret; >> >> + mutex_lock(&dht11->lock); >> if (dht11->timestamp + DHT11_DATA_VALID_TIME < iio_get_time_ns()) { >> reinit_completion(&dht11->completion); >> >> @@ -185,6 +188,7 @@ static int dht11_read_raw(struct iio_dev *iio_dev, >> ret = -EINVAL; >> err: >> dht11->num_edges = -1; >> + mutex_unlock(&dht11->lock); >> return ret; >> } >> >> @@ -268,6 +272,7 @@ static int dht11_probe(struct platform_device *pdev) >> platform_set_drvdata(pdev, iio); >> >> init_completion(&dht11->completion); >> + mutex_init(&dht11->lock); >> iio->name = pdev->name; >> iio->dev.parent = &pdev->dev; >> iio->info = &dht11_iio_info; >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
