On Fri, Mar 08, 2019 at 02:03:27PM -0800, justinpopo6@xxxxxxxxx wrote:
> From: Justin Chen <justinpopo6@xxxxxxxxx>
>
> Indio->mlock is used for protecting the different iio device modes.
> It is currently not being used in this way. Replace the lock with
> an internal lock specifically used for protecting the SPI transfer
> buffer.
>
> Signed-off-by: Justin Chen <justinpopo6@xxxxxxxxx>
> ---
> drivers/iio/adc/ti-ads7950.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
> index 0ad6359..1e47bef 100644
> --- a/drivers/iio/adc/ti-ads7950.c
> +++ b/drivers/iio/adc/ti-ads7950.c
> @@ -56,6 +56,9 @@ struct ti_ads7950_state {
> struct spi_message ring_msg;
> struct spi_message scan_single_msg;
>
> + /* Lock to protect the spi xfer buffers */
> + struct mutex slock;
> +
> struct regulator *reg;
> unsigned int vref_mv;
>
> @@ -268,6 +271,7 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p)
> struct ti_ads7950_state *st = iio_priv(indio_dev);
> int ret;
>
> + mutex_lock(&st->slock);
> ret = spi_sync(st->spi, &st->ring_msg);
> if (ret < 0)
> goto out;
> @@ -276,6 +280,7 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p)
> iio_get_time_ns(indio_dev));
>
> out:
> + mutex_unlock(&st->slock);
> iio_trigger_notify_done(indio_dev->trig);
>
> return IRQ_HANDLED;
> @@ -286,7 +291,7 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
> struct ti_ads7950_state *st = iio_priv(indio_dev);
> int ret, cmd;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->slock);
>
> cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(ch) | st->settings;
> st->single_tx = cmd;
> @@ -298,7 +303,7 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
> ret = st->single_rx;
>
> out:
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->slock);
>
> return ret;
> }
> @@ -432,16 +437,19 @@ static int ti_ads7950_probe(struct spi_device *spi)
> if (ACPI_COMPANION(&spi->dev))
> st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT;
>
> + mutex_init(&st->slock);
> +
> st->reg = devm_regulator_get(&spi->dev, "vref");
> if (IS_ERR(st->reg)) {
> dev_err(&spi->dev, "Failed get get regulator \"vref\"\n");
> - return PTR_ERR(st->reg);
> + ret = PTR_ERR(st->reg);
> + goto error_destroy_mutex;
> }
>
> ret = regulator_enable(st->reg);
> if (ret) {
> dev_err(&spi->dev, "Failed to enable regulator \"vref\"\n");
> - return ret;
> + goto error_destroy_mutex;
> }
>
> ret = iio_triggered_buffer_setup(indio_dev, NULL,
> @@ -463,6 +471,8 @@ static int ti_ads7950_probe(struct spi_device *spi)
> iio_triggered_buffer_cleanup(indio_dev);
> error_disable_reg:
> regulator_disable(st->reg);
> +error_destroy_mutex:
> + mutex_destroy(&st->slock);
If your intention was to do resources cleanup then this is not
what this api was designed for. This is actually for debugging unwanted
subsequent mutex usage.
>
> return ret;
> }
> @@ -475,6 +485,7 @@ static int ti_ads7950_remove(struct spi_device *spi)
> iio_device_unregister(indio_dev);
> iio_triggered_buffer_cleanup(indio_dev);
> regulator_disable(st->reg);
> + mutex_destroy(&st->slock);
>
> return 0;
> }
> --
> 2.7.4
>
