From: Sergiu Cuciurean <sergiu.cuciur...@analog.com> As part of the general cleanup of indio_dev->mlock, this change replaces it with a local lock on the device's state structure.
This is part of a bigger cleanup. Link: https://lore.kernel.org/linux-iio/CA+U=dsoo6yabe5odlp+efnpgfdjk5zeqecegkqjxxcvehlw...@mail.gmail.com/ Signed-off-by: Sergiu Cuciurean <sergiu.cuciur...@analog.com> Signed-off-by: Mircea Caprioru <mircea.capri...@analog.com> --- drivers/iio/adc/vf610_adc.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) diff --git a/drivers/iio/adc/vf610_adc.c b/drivers/iio/adc/vf610_adc.c index 1d794cf3e3f1..b7d583993f0b 100644 --- a/drivers/iio/adc/vf610_adc.c +++ b/drivers/iio/adc/vf610_adc.c @@ -168,6 +168,15 @@ struct vf610_adc { struct completion completion; u16 buffer[8]; + /* + * Lock to protect the device state during a potential concurrent + * read access from userspace. Reading a raw value requires a sequence + * of register writes, then a wait for a completion callback, + * and finally a register read, during which userspace could issue + * another read request. This lock protects a read access from + * ocurring before another one has finished. + */ + struct mutex lock; }; static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 }; @@ -464,11 +473,11 @@ static int vf610_set_conversion_mode(struct iio_dev *indio_dev, { struct vf610_adc *info = iio_priv(indio_dev); - mutex_lock(&indio_dev->mlock); + mutex_lock(&info->lock); info->adc_feature.conv_mode = mode; vf610_adc_calculate_rates(info); vf610_adc_hw_init(info); - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return 0; } @@ -632,9 +641,9 @@ static int vf610_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: case IIO_CHAN_INFO_PROCESSED: - mutex_lock(&indio_dev->mlock); + mutex_lock(&info->lock); if (iio_buffer_enabled(indio_dev)) { - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return -EBUSY; } @@ -645,11 +654,11 @@ static int vf610_read_raw(struct iio_dev *indio_dev, ret = wait_for_completion_interruptible_timeout (&info->completion, VF610_ADC_TIMEOUT); if (ret == 0) { - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return -ETIMEDOUT; } if (ret < 0) { - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return ret; } @@ -668,11 +677,11 @@ static int vf610_read_raw(struct iio_dev *indio_dev, break; default: - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return -EINVAL; } - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: @@ -807,6 +816,9 @@ static int vf610_adc_probe(struct platform_device *pdev) } info = iio_priv(indio_dev); + + mutex_init(&info->lock); + info->dev = &pdev->dev; info->regs = devm_platform_ioremap_resource(pdev, 0); -- 2.25.1
