From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: Re: [PATCH 07/14] iio: triggers: on pollfunc attach, complete iio_dev if NULL Date: Fri, 29 Dec 2017 17:23:37 +0000 Message-ID: <20171229172337.6226de69@archlinux> References: <1513955241-10985-1-git-send-email-eugen.hristev@microchip.com> <1513955241-10985-8-git-send-email-eugen.hristev@microchip.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1513955241-10985-8-git-send-email-eugen.hristev@microchip.com> Sender: linux-input-owner@vger.kernel.org To: Eugen Hristev Cc: nicolas.ferre@microchip.com, ludovic.desroches@microchip.com, alexandre.belloni@free-electrons.com, linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, dmitry.torokhov@gmail.com List-Id: devicetree@vger.kernel.org On Fri, 22 Dec 2017 17:07:14 +0200 Eugen Hristev 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 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. > --- > 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. > + 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);