[PATCH 3.16 340/366] iio: iio-trig-periodic-rtc: Free trigger resource correctly

Ben Hutchings
2018-11-11T20:29:12Z

From: Ben Hutchings <ben.hutchings@codethink.co.uk>

This is based on upstream commit 10e840dfb0b7, which did not touch the
iio-trig-periodic-rtc driver because it has been removed upstream.

The following explanation comes from that commit:

These stand-alone trigger drivers were using iio_trigger_put()
where they should have been using iio_trigger_free(). The
iio_trigger_put() adds a module_put which is bad since they
never did a module_get.

In the sysfs driver, module_get/put's are used as triggers are
added & removed. This extra module_put() occurs on an error path
in the probe routine (probably rare).

In the bfin-timer & interrupt trigger drivers, the module resources
are not explicitly managed, so it's doing a put on something that
was never get'd. It occurs on the probe error path and on the
remove path (not so rare).

Tested with the sysfs trigger driver.
The bfin & interrupt drivers were build tested & inspected only.

This was build tested only.

Cc: Alison Schofield <amsfield22@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/staging/iio/trigger/iio-trig-periodic-rtc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/staging/iio/trigger/iio-trig-periodic-rtc.c
+++ b/drivers/staging/iio/trigger/iio-trig-periodic-rtc.c
@@ -123,7 +123,7 @@ static int iio_trig_periodic_rtc_probe(s
trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
if (!trig_info) {
ret = -ENOMEM;
- goto error_put_trigger_and_remove_from_list;
+ goto error_free_trigger_and_remove_from_list;
}
iio_trigger_set_drvdata(trig, trig_info);
trig->ops = &iio_prtc_trigger_ops;
@@ -151,9 +151,9 @@ error_close_rtc:
rtc_class_close(trig_info->rtc);
error_free_trig_info:
kfree(trig_info);
-error_put_trigger_and_remove_from_list:
+error_free_trigger_and_remove_from_list:
list_del(&trig->alloc_list);
- iio_trigger_put(trig);
+ iio_trigger_free(trig);
error_free_completed_registrations:
list_for_each_entry_safe(trig,
trig2,