[PATCH 07/14] iio: triggers: on pollfunc attach, complete iio_dev if NULL
From: jic23@kernel.org (Jonathan Cameron)
Date: 2017-12-29 17:23:43
Also in:
linux-devicetree, linux-iio, linux-input, lkml
On Fri, 22 Dec 2017 17:07:14 +0200 Eugen Hristev [off-list ref] wrote:
When attaching a pollfunc to a trigger, if the pollfunc does not have an associated iio_dev pointer, just use the private data iio_dev pointer from the trigger to fill in the poll func required iio_dev reference. Signed-off-by: Eugen Hristev <redacted>
I'm yet to be convinced this is necessary rather than using a callback buffer. It's also decidedly unsafe as there is no particular reason in general to assume the private data is an iio_dev.
quoted hunk ↗ jump to hunk
--- drivers/iio/industrialio-trigger.c | 9 +++++++++ include/linux/iio/trigger_consumer.h | 2 ++ 2 files changed, 11 insertions(+)diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c index 8565c92..ab180bd 100644 --- a/drivers/iio/industrialio-trigger.c +++ b/drivers/iio/industrialio-trigger.c@@ -272,6 +272,15 @@ int iio_trigger_attach_poll_func(struct iio_trigger *trig, bool notinuse = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER); + /* + * If we did not get a iio_dev in the poll func, attempt to + * obtain the trigger's owner's device struct + */ + if (!pf->indio_dev) + pf->indio_dev = iio_trigger_get_drvdata(trig);
That isn't always valid. Triggers don't always have a iio_dev associated with them at all.
quoted hunk ↗ jump to hunk
+ if (!pf->indio_dev) + return -EINVAL; + /* Prevent the module from being removed whilst attached to a trigger */ __module_get(pf->indio_dev->driver_module);diff --git a/include/linux/iio/trigger_consumer.h b/include/linux/iio/trigger_consumer.h index aeefcdb..36e2a02 100644 --- a/include/linux/iio/trigger_consumer.h +++ b/include/linux/iio/trigger_consumer.h@@ -63,6 +63,8 @@ int iio_triggered_buffer_predisable(struct iio_dev *indio_dev); /* * Two functions for the uncommon case when we need to attach or detach * a specific pollfunc to and from a trigger + * If the pollfunc has a NULL iio_dev pointer, it will be filled from the + * trigger struct. */ int iio_trigger_attach_poll_func(struct iio_trigger *trig, struct iio_poll_func *pf);