On 09/03/17 20:46, Alison Schofield wrote:
> The IIO subsystem is redefining iio_dev->mlock to be used by
> the IIO core only for protecting device operating mode changes.
> ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes.
>
> In this driver, mlock was being used to protect hardware state
> changes. Replace it with a lock in the devices global data.
>
> Signed-off-by: Alison Schofield <amsfield22@xxxxxxxxx>
Applied to the togreg branch of iio.git and pushed out as
testing for the autobuilders to play with it.
Thanks,
Jonathan
> ---
>
> Jonathan et al,
>
> If you still want to do this change, is it time to change the
> iio_dev->mlock comment back to [INTERN] in iio.h so that it
> doesn't get any new uses whilst we are migrating. Yes?
>
> I'd like to give this as a task to the outreachy applicants. There
> are ~70 mlock usages spread amongst ~15 iio drivers in staging.
> Are you ready for a wave of these?
Yes. That was an easy question ;)
Make sure that they fully review the locking whilst at it though
as chances are some of it may be less than ideal!
Jonathan
>
>
> drivers/staging/iio/frequency/ad9832.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/iio/frequency/ad9832.c b/drivers/staging/iio/frequency/ad9832.c
> index 8d40c8e..c992648 100644
> --- a/drivers/staging/iio/frequency/ad9832.c
> +++ b/drivers/staging/iio/frequency/ad9832.c
> @@ -84,6 +84,7 @@
> * @freq_msg: tuning word spi message
> * @phase_xfer: tuning word spi transfer
> * @phase_msg: tuning word spi message
> + * @lock protect sensor state
> * @data: spi transmit buffer
> * @phase_data: tuning word spi transmit buffer
> * @freq_data: tuning word spi transmit buffer
> @@ -103,6 +104,7 @@ struct ad9832_state {
> struct spi_message freq_msg;
> struct spi_transfer phase_xfer[2];
> struct spi_message phase_msg;
> + struct mutex lock; /* protect sensor state */
> /*
> * DMA (thus cache coherency maintenance) requires the
> * transfer buffers to live in their own cache lines.
> @@ -177,7 +179,7 @@ static ssize_t ad9832_write(struct device *dev, struct device_attribute *attr,
> if (ret)
> goto error_ret;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> switch ((u32)this_attr->address) {
> case AD9832_FREQ0HM:
> case AD9832_FREQ1HM:
> @@ -238,7 +240,7 @@ static ssize_t ad9832_write(struct device *dev, struct device_attribute *attr,
> default:
> ret = -ENODEV;
> }
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> error_ret:
> return ret ? ret : len;
>
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