media: v4l2-async: Fix error handling on steps after finding a match

[ Upstream commit 7345d6d ]

Once an async connection is found to be matching with an fwnode, a
sub-device may be registered (in case it wasn't already), its bound
operation is called, ancillary links are created, the async connection
is added to the sub-device's list of connections and removed from the
global waiting connection list. Further on, the sub-device's possible own
notifier is searched for possible additional matches.

Fix these specific issues:

- If v4l2_async_match_notify() failed before the sub-notifier handling,
  the async connection was unbound and its entry removed from the
  sub-device's async connection list. The latter part was also done in
  v4l2_async_match_notify().

- The async connection's sd field was only set after creating ancillary
  links in v4l2_async_match_notify(). It was however dereferenced in
  v4l2_async_unbind_subdev_one(), which was called on error path of
  v4l2_async_match_notify() failure.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: "Yew, Chang Ching" <chang.ching.yew@intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Sakari Ailus

drivers/media/v4l2-core/v4l2-async.c

@@ -339,7 +339,6 @@ static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
 				   struct v4l2_subdev *sd,
 				   struct v4l2_async_connection *asc)
 {
-	struct v4l2_async_notifier *subdev_notifier;
 	bool registered = false;
 	int ret;
 
@@ -385,6 +384,25 @@ static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
 	dev_dbg(notifier_dev(notifier), "v4l2-async: %s bound (ret %d)\n",
 		dev_name(sd->dev), ret);
 
+	return 0;
+
+err_call_unbind:
+	v4l2_async_nf_call_unbind(notifier, sd, asc);
+	list_del(&asc->asc_subdev_entry);
+
+err_unregister_subdev:
+	if (registered)
+		v4l2_device_unregister_subdev(sd);
+
+	return ret;
+}
+
+static int
+v4l2_async_nf_try_subdev_notifier(struct v4l2_async_notifier *notifier,
+				  struct v4l2_subdev *sd)
+{
+	struct v4l2_async_notifier *subdev_notifier;
+
 	/*
 	 * See if the sub-device has a notifier. If not, return here.
 	 */
@@ -400,16 +418,6 @@ static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
 	subdev_notifier->parent = notifier;
 
 	return v4l2_async_nf_try_all_subdevs(subdev_notifier);
-
-err_call_unbind:
-	v4l2_async_nf_call_unbind(notifier, sd, asc);
-	list_del(&asc->asc_subdev_entry);
-
-err_unregister_subdev:
-	if (registered)
-		v4l2_device_unregister_subdev(sd);
-
-	return ret;
 }
 
 /* Test all async sub-devices in a notifier for a match. */
@@ -441,6 +449,10 @@ v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier)
 		if (ret < 0)
 			return ret;
 
+		ret = v4l2_async_nf_try_subdev_notifier(notifier, sd);
+		if (ret < 0)
+			return ret;
+
 		/*
 		 * v4l2_async_match_notify() may lead to registering a
 		 * new notifier and thus changing the async subdevs
@@ -823,7 +835,11 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 			ret = v4l2_async_match_notify(notifier, v4l2_dev, sd,
 						      asc);
 			if (ret)
-				goto err_unbind;
+				goto err_unlock;
+
+			ret = v4l2_async_nf_try_subdev_notifier(notifier, sd);
+			if (ret)
+				goto err_unbind_one;
 
 			ret = v4l2_async_nf_try_complete(notifier);
 			if (ret)
@@ -847,9 +863,10 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 	if (subdev_notifier)
 		v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
 
-	if (asc)
-		v4l2_async_unbind_subdev_one(notifier, asc);
+err_unbind_one:
+	v4l2_async_unbind_subdev_one(notifier, asc);
 
+err_unlock:
 	mutex_unlock(&list_lock);
 
 	return ret;