| Message ID | 20200514085018.79948-1-sergiu.cuciurean@analog.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | iio: stm32-dac: Replace indio_dev->mlock with own device lock | expand |
On Thu, 14 May 2020 11:50:12 +0300 Sergiu Cuciurean <sergiu.cuciurean@analog.com> 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 <sergiu.cuciurean@analog.com> > --- > 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 <sergiu.cuciurean@analog.com> 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 <sergiu.cuciurean@analog.com> >> --- >> 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; >
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;
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 <sergiu.cuciurean@analog.com> --- drivers/iio/dac/stm32-dac.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)