From: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx> 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+eFNPGFDjk5ZeQEceGkqjxXcVEhLWubw@xxxxxxxxxxxxxx/ Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx> Signed-off-by: Mircea Caprioru <mircea.caprioru@xxxxxxxxxx> --- drivers/iio/adc/rockchip_saradc.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c index 1f3d7d639d37..80084c526cc6 100644 --- a/drivers/iio/adc/rockchip_saradc.c +++ b/drivers/iio/adc/rockchip_saradc.c @@ -53,6 +53,15 @@ struct rockchip_saradc { const struct rockchip_saradc_data *data; u16 last_val; const struct iio_chan_spec *last_chan; + /* + * 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 void rockchip_saradc_power_down(struct rockchip_saradc *info) @@ -92,17 +101,17 @@ static int rockchip_saradc_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: - mutex_lock(&indio_dev->mlock); + mutex_lock(&info->lock); ret = rockchip_saradc_conversion(info, chan); if (ret) { rockchip_saradc_power_down(info); - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return ret; } *val = info->last_val; - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: ret = regulator_get_voltage(info->vref); @@ -254,7 +263,7 @@ static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p) int ret; int i, j = 0; - mutex_lock(&i_dev->mlock); + mutex_lock(&info->lock); for_each_set_bit(i, i_dev->active_scan_mask, i_dev->masklength) { const struct iio_chan_spec *chan = &i_dev->channels[i]; @@ -271,7 +280,7 @@ static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p) iio_push_to_buffers_with_timestamp(i_dev, &data, iio_get_time_ns(i_dev)); out: - mutex_unlock(&i_dev->mlock); + mutex_unlock(&info->lock); iio_trigger_notify_done(i_dev->trig); @@ -332,6 +341,8 @@ static int rockchip_saradc_probe(struct platform_device *pdev) info->reset = NULL; } + mutex_init(&info->lock); + init_completion(&info->completion); irq = platform_get_irq(pdev, 0); -- 2.25.1
