As part of the general cleanup of indio_dev->mlock, this change replaces
it with a local lock on the device's state structure.
Signed-off-by: Sergiu Cuciurean <[email protected]>
---
drivers/iio/dac/stm32-dac.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c
index f22c1d9129b2..74b9474c8590 100644
--- a/drivers/iio/dac/stm32-dac.c
+++ b/drivers/iio/dac/stm32-dac.c
@@ -26,9 +26,11 @@
/**
* struct stm32_dac - private data of DAC driver
* @common: reference to DAC common data
+ * @lock: lock to protect the data buffer during regmap ops
*/
struct stm32_dac {
struct stm32_dac_common *common;
+ struct mutex lock;
};
static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
@@ -58,10 +60,10 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
int ret;
/* already enabled / disabled ? */
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&dac->lock);
ret = stm32_dac_is_enabled(indio_dev, ch);
if (ret < 0 || enable == !!ret) {
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&dac->lock);
return ret < 0 ? ret : 0;
}
@@ -69,13 +71,13 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
ret = pm_runtime_get_sync(dev);
if (ret < 0) {
pm_runtime_put_noidle(dev);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&dac->lock);
return ret;
}
}
ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&dac->lock);
if (ret < 0) {
dev_err(&indio_dev->dev, "%s failed\n", en ?
"Enable" : "Disable");
@@ -328,6 +330,8 @@ static int stm32_dac_probe(struct platform_device *pdev)
indio_dev->info = &stm32_dac_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
+ mutex_init(&dac->lock);
+
ret = stm32_dac_chan_of_init(indio_dev);
if (ret < 0)
return ret;
--
2.17.1
On Thu, 14 May 2020 11:50:12 +0300
Sergiu Cuciurean <[email protected]> wrote:
> As part of the general cleanup of indio_dev->mlock, this change replaces
> it with a local lock on the device's state structure.
>
> Signed-off-by: Sergiu Cuciurean <[email protected]>
> ---
> drivers/iio/dac/stm32-dac.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c
> index f22c1d9129b2..74b9474c8590 100644
> --- a/drivers/iio/dac/stm32-dac.c
> +++ b/drivers/iio/dac/stm32-dac.c
> @@ -26,9 +26,11 @@
> /**
> * struct stm32_dac - private data of DAC driver
> * @common: reference to DAC common data
> + * @lock: lock to protect the data buffer during regmap ops
In this particular case I'm not sure that's what mlock was being used for.
I think it's about avoiding races around checking if powered down and
actually doing it.
> */
> struct stm32_dac {
> struct stm32_dac_common *common;
> + struct mutex lock;
> };
>
> static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
> @@ -58,10 +60,10 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
> int ret;
>
> /* already enabled / disabled ? */
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&dac->lock);
> ret = stm32_dac_is_enabled(indio_dev, ch);
> if (ret < 0 || enable == !!ret) {
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&dac->lock);
> return ret < 0 ? ret : 0;
> }
>
> @@ -69,13 +71,13 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
> ret = pm_runtime_get_sync(dev);
> if (ret < 0) {
> pm_runtime_put_noidle(dev);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&dac->lock);
> return ret;
> }
> }
>
> ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&dac->lock);
> if (ret < 0) {
> dev_err(&indio_dev->dev, "%s failed\n", en ?
> "Enable" : "Disable");
> @@ -328,6 +330,8 @@ static int stm32_dac_probe(struct platform_device *pdev)
> indio_dev->info = &stm32_dac_iio_info;
> indio_dev->modes = INDIO_DIRECT_MODE;
>
> + mutex_init(&dac->lock);
> +
> ret = stm32_dac_chan_of_init(indio_dev);
> if (ret < 0)
> return ret;
On 5/16/20 5:35 PM, Jonathan Cameron wrote:
> On Thu, 14 May 2020 11:50:12 +0300
> Sergiu Cuciurean <[email protected]> wrote:
>
>> As part of the general cleanup of indio_dev->mlock, this change replaces
>> it with a local lock on the device's state structure.
>>
>> Signed-off-by: Sergiu Cuciurean <[email protected]>
>> ---
>> drivers/iio/dac/stm32-dac.c | 12 ++++++++----
>> 1 file changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c
>> index f22c1d9129b2..74b9474c8590 100644
>> --- a/drivers/iio/dac/stm32-dac.c
>> +++ b/drivers/iio/dac/stm32-dac.c
>> @@ -26,9 +26,11 @@
>> /**
>> * struct stm32_dac - private data of DAC driver
>> * @common: reference to DAC common data
>> + * @lock: lock to protect the data buffer during regmap ops
>
> In this particular case I'm not sure that's what mlock was being used for.
> I think it's about avoiding races around checking if powered down and
> actually doing it.
Hi Sergiu,
Indeed, purpose is to protect against a race here when reading CR, and
updating it via regmap (this also makes the subsequent pm_runtime calls
to be balanced based on this).
(Side note: there is no data buffer involved for the DAC.)
Could you please update the comment ?
Thanks,
Fabrice
>
>
>> */
>> struct stm32_dac {
>> struct stm32_dac_common *common;
>> + struct mutex lock;
>> };
>>
>> static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
>> @@ -58,10 +60,10 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
>> int ret;
>>
>> /* already enabled / disabled ? */
>> - mutex_lock(&indio_dev->mlock);
>> + mutex_lock(&dac->lock);
>> ret = stm32_dac_is_enabled(indio_dev, ch);
>> if (ret < 0 || enable == !!ret) {
>> - mutex_unlock(&indio_dev->mlock);
>> + mutex_unlock(&dac->lock);
>> return ret < 0 ? ret : 0;
>> }
>>
>> @@ -69,13 +71,13 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
>> ret = pm_runtime_get_sync(dev);
>> if (ret < 0) {
>> pm_runtime_put_noidle(dev);
>> - mutex_unlock(&indio_dev->mlock);
>> + mutex_unlock(&dac->lock);
>> return ret;
>> }
>> }
>>
>> ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
>> - mutex_unlock(&indio_dev->mlock);
>> + mutex_unlock(&dac->lock);
>> if (ret < 0) {
>> dev_err(&indio_dev->dev, "%s failed\n", en ?
>> "Enable" : "Disable");
>> @@ -328,6 +330,8 @@ static int stm32_dac_probe(struct platform_device *pdev)
>> indio_dev->info = &stm32_dac_iio_info;
>> indio_dev->modes = INDIO_DIRECT_MODE;
>>
>> + mutex_init(&dac->lock);
>> +
>> ret = stm32_dac_chan_of_init(indio_dev);
>> if (ret < 0)
>> return ret;
>