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Date: Mon, 30 Mar 2020 14:39:21 +0100
From: Jonathan Cameron <jic23@...23.retrosnub.co.uk>
To: Rohit Sarkar <rohitsarkar5398@...il.com>
Cc: linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
dragos.bogdan@...log.com
Subject: Re: [PATCH v7] iio: adc: max1363: replace uses of mlock
On Sun, 22 Mar 2020 17:53:58 +0000
Jonathan Cameron <jic23@...nel.org> wrote:
> On Sun, 15 Mar 2020 21:34:58 +0530
> Rohit Sarkar <rohitsarkar5398@...il.com> wrote:
>
> > Replace usage indio_dev's mlock with either local lock or
> > iio_device_claim_direct_mode.
> >
> > Signed-off-by: Rohit Sarkar <rohitsarkar5398@...il.com>
> Applied to the togreg branch of iio.git and pushed out as testing.
Not my best review and strangely missed any warnings in my
local build tests. 0-day came back pointing this out earlier
(see inline). I've fixed up.
>
> Thanks,
>
> Jonathan
>
> > ---
> > Changelog v6 -> v7
> > * Fix failure handling logic
> >
> > Changelog v5 -> v6
> > * Minor failure handling fixes
> >
> > Changelog v4 -> v5
> > * Use local lock too at places where driver state needs to be protected.
> >
> > Changelog v3 -> v4
> > * Fix indentation
> >
> > Changelog v2 -> v3
> > * use iio_device_claim_direct when switching modes
> > * replace mlock usage in max1363_write_event_config
> >
> > Changelog v1 -> v2
> > * Fix indentation
> >
> > drivers/iio/adc/max1363.c | 37 ++++++++++++++++++++++++++++---------
> > 1 file changed, 28 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/iio/adc/max1363.c b/drivers/iio/adc/max1363.c
> > index 5c2cc61b666e..12d72bf3f12a 100644
> > --- a/drivers/iio/adc/max1363.c
> > +++ b/drivers/iio/adc/max1363.c
> > @@ -150,6 +150,7 @@ struct max1363_chip_info {
> > * @current_mode: the scan mode of this chip
> > * @requestedmask: a valid requested set of channels
> > * @reg: supply regulator
> > + * @lock lock to ensure state is consistent
> > * @monitor_on: whether monitor mode is enabled
> > * @monitor_speed: parameter corresponding to device monitor speed setting
> > * @mask_high: bitmask for enabled high thresholds
> > @@ -169,6 +170,7 @@ struct max1363_state {
> > const struct max1363_mode *current_mode;
> > u32 requestedmask;
> > struct regulator *reg;
> > + struct mutex lock;
> >
> > /* Using monitor modes and buffer at the same time is
> > currently not supported */
> > @@ -364,7 +366,13 @@ static int max1363_read_single_chan(struct iio_dev *indio_dev,
> > struct max1363_state *st = iio_priv(indio_dev);
> > struct i2c_client *client = st->client;
> >
> > - mutex_lock(&indio_dev->mlock);
> > + ret = iio_device_claim_direct_mode(indio_dev);
> > + if (ret)
> > + return ret;
> > + mutex_lock(&st->lock);
> > +
> > + if (ret < 0)
> > + goto error_ret;
> > /*
> > * If monitor mode is enabled, the method for reading a single
> > * channel will have to be rather different and has not yet
> > @@ -372,7 +380,7 @@ static int max1363_read_single_chan(struct iio_dev *indio_dev,
> > *
> > * Also, cannot read directly if buffered capture enabled.
> > */
> > - if (st->monitor_on || iio_buffer_enabled(indio_dev)) {
> > + if (st->monitor_on) {
> > ret = -EBUSY;
> > goto error_ret;
> > }
> > @@ -404,8 +412,10 @@ static int max1363_read_single_chan(struct iio_dev *indio_dev,
> > data = rxbuf[0];
> > }
> > *val = data;
> > +
> > error_ret:
> > - mutex_unlock(&indio_dev->mlock);
> > + mutex_unlock(&st->lock);
> > + iio_device_release_direct_mode(indio_dev);
> > return ret;
> >
> > }
> > @@ -705,9 +715,9 @@ static ssize_t max1363_monitor_store_freq(struct device *dev,
> > if (!found)
> > return -EINVAL;
> >
> > - mutex_lock(&indio_dev->mlock);
> > + mutex_lock(&st->lock);
> > st->monitor_speed = i;
> > - mutex_unlock(&indio_dev->mlock);
> > + mutex_unlock(&st->lock);
> >
> > return 0;
> > }
> > @@ -810,12 +820,12 @@ static int max1363_read_event_config(struct iio_dev *indio_dev,
> > int val;
> > int number = chan->channel;
> >
> > - mutex_lock(&indio_dev->mlock);
> > + mutex_lock(&st->lock);
> > if (dir == IIO_EV_DIR_FALLING)
> > val = (1 << number) & st->mask_low;
> > else
> > val = (1 << number) & st->mask_high;
> > - mutex_unlock(&indio_dev->mlock);
> > + mutex_unlock(&st->lock);
> >
> > return val;
> > }
> > @@ -962,7 +972,14 @@ static int max1363_write_event_config(struct iio_dev *indio_dev,
> > u16 unifiedmask;
> > int number = chan->channel;
> >
> > - mutex_lock(&indio_dev->mlock);
> > + ret = iio_device_claim_direct_mode(indio_dev);
> > + if (ret)
> > + return ret;
> > + mutex_lock(&st->lock);
> > +
We just checked ret. No need to do it again :)
I've dropped this second test.
Jonathan
> > + if (ret < 0)
> > + goto error_ret;
> > +
> > unifiedmask = st->mask_low | st->mask_high;
> > if (dir == IIO_EV_DIR_FALLING) {
> >
> > @@ -989,7 +1006,8 @@ static int max1363_write_event_config(struct iio_dev *indio_dev,
> >
> > max1363_monitor_mode_update(st, !!(st->mask_high | st->mask_low));
> > error_ret:
> > - mutex_unlock(&indio_dev->mlock);
> > + mutex_unlock(&st->lock);
> > + iio_device_release_direct_mode(indio_dev);
> >
> > return ret;
> > }
> > @@ -1587,6 +1605,7 @@ static int max1363_probe(struct i2c_client *client,
> >
> > st = iio_priv(indio_dev);
> >
> > + mutex_init(&st->lock);
> > st->reg = devm_regulator_get(&client->dev, "vcc");
> > if (IS_ERR(st->reg)) {
> > ret = PTR_ERR(st->reg);
>
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