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SubjectRe: [PATCH 1/4] iio: dht11: Add locking
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
>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
> 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;
>



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