linux-kernel - [PATCH 2/2] media: v4l2-async: Make subdev notifier cleanup conditional

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Date:   Wed,  9 Jun 2021 13:54:57 +0200
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Niklas Söderlund 
        <niklas.soderlund+renesas@...natech.se>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Sebastian Reichel <sre@...nel.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Subject: [PATCH 2/2] media: v4l2-async: Make subdev notifier cleanup conditional

A dedicated subdev notified is registered when using the helper
dedicated to sensors (v4l2_async_register_subdev_sensor_common),
but this is not the case when a driver uses v4l2_async_register_subdev
directly.

As a result, add a conditional check to deal with the dedicated subdev
notifier only when necessary at the async subdev unregister step
(and avoid operating on/freeing an unallocated notifier).

Fixes: aef69d54755d ("media: v4l: fwnode: Add a convenience function for registering sensors")
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@...tlin.com>
---
 drivers/media/v4l2-core/v4l2-async.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index cd9e78c63791..e0f4f7551ff3 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -780,10 +780,12 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
 
 	mutex_lock(&list_lock);
 
-	__v4l2_async_notifier_unregister(sd->subdev_notifier);
-	__v4l2_async_notifier_cleanup(sd->subdev_notifier);
-	kfree(sd->subdev_notifier);
-	sd->subdev_notifier = NULL;
+	if (sd->subdev_notifier) {
+		__v4l2_async_notifier_unregister(sd->subdev_notifier);
+		__v4l2_async_notifier_cleanup(sd->subdev_notifier);
+		kfree(sd->subdev_notifier);
+		sd->subdev_notifier = NULL;
+	}
 
 	if (sd->asd) {
 		struct v4l2_async_notifier *notifier = sd->notifier;
-- 
2.31.1