[PATCH 2/2] media: v4l: async: Properly check for a notifier initialised or registered

[Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>]

Properly check that a notifier was never initialised or register. This can
now be done by looking at the entry in the notifier list, not the V4L2
device or sub-device that are set in the initialiser now.

Fixes: b8ec754ae4c5 ("media: v4l: async: Set v4l2_device and subdev in async notifier init")
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
 drivers/media/v4l2-core/v4l2-async.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 2ff35d5d60f2..3b43d6285dfe 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -630,12 +630,14 @@ EXPORT_SYMBOL(v4l2_async_nf_register);
 static void
 __v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
 {
-	if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
+	/* Return here if the notifier is never initialised or registered. */
+	if (!notifier->notifier_entry.next ||
+	    list_empty(&notifier->notifier_entry))
 		return;
 
 	v4l2_async_nf_unbind_all_subdevs(notifier);
 
-	list_del(&notifier->notifier_entry);
+	list_del_init(&notifier->notifier_entry);
 }
 
 void v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
-- 
2.39.2