media: v4l: async: Drop duplicate handling when adding connections

The connections are checked for duplicates already when the notifier is
registered. This is effectively a sanity check for driver (and possibly
obscure firmware) bugs. Don't do this when adding the connection.

Retain the int return type for now. It'll be needed very soon again.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de> # imx6qp
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> # rcar + adv746x
Tested-by: Aishwarya Kothari <aishwarya.kothari@toradex.com> # Apalis i.MX6Q with TC358743
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> # Renesas RZ/G2L SMARC
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

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

@@ -471,14 +471,11 @@ v4l2_async_nf_has_async_match_entry(struct v4l2_async_notifier *notifier,
 
 /*
  * Find out whether an async sub-device was set up already or whether it exists
- * in a given notifier. The skip_self argument is used to skip testing the same
- * sub-device in the notifier in case the sub-device has been already added to
- * the notifier.
+ * in a given notifier.
  */
 static bool
 v4l2_async_nf_has_async_match(struct v4l2_async_notifier *notifier,
-			      struct v4l2_async_match_desc *match,
-			      bool skip_self)
+			      struct v4l2_async_match_desc *match)
 {
 	struct v4l2_async_connection *asc;
 
@@ -486,7 +483,7 @@ v4l2_async_nf_has_async_match(struct v4l2_async_notifier *notifier,
 
 	/* Check that an asd is not being added more than once. */
 	list_for_each_entry(asc, &notifier->asc_list, asc_entry) {
-		if (skip_self && &asc->match == match)
+		if (&asc->match == match)
 			continue;
 		if (v4l2_async_match_equal(&asc->match, match))
 			return true;
@@ -501,16 +498,14 @@ v4l2_async_nf_has_async_match(struct v4l2_async_notifier *notifier,
 }
 
 static int v4l2_async_nf_match_valid(struct v4l2_async_notifier *notifier,
-				     struct v4l2_async_match_desc *match,
-				     bool skip_self)
+				     struct v4l2_async_match_desc *match)
 {
 	struct device *dev = notifier_dev(notifier);
 
 	switch (match->type) {
 	case V4L2_ASYNC_MATCH_TYPE_I2C:
 	case V4L2_ASYNC_MATCH_TYPE_FWNODE:
-		if (v4l2_async_nf_has_async_match(notifier, match,
-						  skip_self)) {
+		if (v4l2_async_nf_has_async_match(notifier, match)) {
 			dev_dbg(dev, "v4l2-async: match descriptor already listed in a notifier\n");
 			return -EEXIST;
 		}
@@ -541,7 +536,7 @@ static int __v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
 	mutex_lock(&list_lock);
 
 	list_for_each_entry(asc, &notifier->asc_list, asc_entry) {
-		ret = v4l2_async_nf_match_valid(notifier, &asc->match, true);
+		ret = v4l2_async_nf_match_valid(notifier, &asc->match);
 		if (ret)
 			goto err_unlock;
 
@@ -670,19 +665,13 @@ EXPORT_SYMBOL_GPL(v4l2_async_nf_cleanup);
 static int __v4l2_async_nf_add_connection(struct v4l2_async_notifier *notifier,
 					  struct v4l2_async_connection *asc)
 {
-	int ret;
-
 	mutex_lock(&list_lock);
 
-	ret = v4l2_async_nf_match_valid(notifier, &asc->match, false);
-	if (ret)
-		goto unlock;
-
 	list_add_tail(&asc->asc_entry, &notifier->asc_list);
 
-unlock:
 	mutex_unlock(&list_lock);
-	return ret;
+
+	return 0;
 }
 
 struct v4l2_async_connection *