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Subject[PATCHv2] iio: Fix error handling in iio_trigger_attach_poll_func
Date
When attaching a pollfunc iio_trigger_attach_poll_func will allocate a
virtual irq and call the driver's set_trigger_state function. Fix error
handling to undo previous steps if any fails.

In particular this fixes handling errors from a driver's
set_trigger_state function. When using triggered buffers a failure to
enable the trigger used to make the buffer unusable.

Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
---

Previous version was sent as a RFC. This version also properly handles errors
from iio_trigger_get_irq and request_threaded_irq.

Calling request_threaded_irq with a negative/invalid irq parameter might work
and return an error but let's not rely on that.

drivers/iio/industrialio-trigger.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index ae2806a..0c52dfe 100644
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -210,22 +210,35 @@ static int iio_trigger_attach_poll_func(struct iio_trigger *trig,

/* Prevent the module from being removed whilst attached to a trigger */
__module_get(pf->indio_dev->info->driver_module);
+
+ /* Get irq number */
pf->irq = iio_trigger_get_irq(trig);
+ if (pf->irq < 0)
+ goto out_put_module;
+
+ /* Request irq */
ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
pf->type, pf->name,
pf);
- if (ret < 0) {
- module_put(pf->indio_dev->info->driver_module);
- return ret;
- }
+ if (ret < 0)
+ goto out_put_irq;

+ /* Enable trigger in driver */
if (trig->ops && trig->ops->set_trigger_state && notinuse) {
ret = trig->ops->set_trigger_state(trig, true);
if (ret < 0)
- module_put(pf->indio_dev->info->driver_module);
+ goto out_free_irq;
}

return ret;
+
+out_free_irq:
+ free_irq(pf->irq, pf);
+out_put_irq:
+ iio_trigger_put_irq(trig, pf->irq);
+out_put_module:
+ module_put(pf->indio_dev->info->driver_module);
+ return ret;
}

static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
--
2.5.5
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