On 10/04/13 12:07, Lars-Peter Clausen wrote:
> We need to make sure that in-kernel users of iio_update_buffers() do not race
> against each other or against unregistration of the device. So we need to take
> both the mlock and the info_exist_lock when calling iio_update_buffers() from a
> in-kernel consumer.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Applied to the togreg branch of iio.git
Thanks,
Jonathan
> ---
> No changes since v1
> ---
> drivers/iio/industrialio-buffer.c | 29 ++++++++++++++++++++++++++---
> 1 file changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index 5a46c57..d6a5455 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -509,7 +509,7 @@ void iio_disable_all_buffers(struct iio_dev *indio_dev)
> indio_dev->setup_ops->postdisable(indio_dev);
> }
>
> -int iio_update_buffers(struct iio_dev *indio_dev,
> +static int __iio_update_buffers(struct iio_dev *indio_dev,
> struct iio_buffer *insert_buffer,
> struct iio_buffer *remove_buffer)
> {
> @@ -674,6 +674,29 @@ error_ret:
>
> return ret;
> }
> +
> +int iio_update_buffers(struct iio_dev *indio_dev,
> + struct iio_buffer *insert_buffer,
> + struct iio_buffer *remove_buffer)
> +{
> + int ret;
> +
> + mutex_lock(&indio_dev->info_exist_lock);
> + mutex_lock(&indio_dev->mlock);
> +
> + if (indio_dev->info == NULL) {
> + ret = -ENODEV;
> + goto out_unlock;
> + }
> +
> + ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
> +
> +out_unlock:
> + mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&indio_dev->info_exist_lock);
> +
> + return ret;
> +}
> EXPORT_SYMBOL_GPL(iio_update_buffers);
>
> ssize_t iio_buffer_store_enable(struct device *dev,
> @@ -699,10 +722,10 @@ ssize_t iio_buffer_store_enable(struct device *dev,
> goto done;
>
> if (requested_state)
> - ret = iio_update_buffers(indio_dev,
> + ret = __iio_update_buffers(indio_dev,
> indio_dev->buffer, NULL);
> else
> - ret = iio_update_buffers(indio_dev,
> + ret = __iio_update_buffers(indio_dev,
> NULL, indio_dev->buffer);
>
> if (ret < 0)
>
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