iio: Fix error handling in iio_trigger_attach_poll_func

commit 99543823357966ac938d9a310947e731b67338e6 upstream.

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>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/staging/iio/industrialio-trigger.c b/drivers/staging/iio/industrialio-trigger.c
index 57c8d83..fa6e882 100644 (file)
--- a/drivers/staging/iio/industrialio-trigger.c
+++ b/drivers/staging/iio/industrialio-trigger.c
@@ -218,22 +218,35 @@ static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 
        /* Prevent the module 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_dettach_poll_func(struct iio_trigger *trig,