[PATCH] v4l: rcar-vin: Simplify rvin_group_notify_{bound,unbind}

[Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>]

Use a container_of macro to obtain the graph entity object from the ASD
This removes the error conditions, and reduces the lock contention.

(The locking may even be potentially removed)

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
---

Hi Niklas,

While working through the Multi camera setup, we came across this improvement.

If this code isn't yet upstream, feel free to squash this change into your
existing branch if you wish.

Regards

Kieran

 drivers/media/platform/rcar-vin/rcar-core.c | 28 ++++++----------------------
 drivers/media/platform/rcar-vin/rcar-vin.h  |  3 +++
 2 files changed, 9 insertions(+), 22 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index 8393a1598660..b4fc7b56c8a1 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -688,20 +688,11 @@ static void rvin_group_notify_unbind(struct v4l2_async_notifier *notifier,
 				     struct v4l2_async_subdev *asd)
 {
 	struct rvin_dev *vin = notifier_to_vin(notifier);
-	unsigned int i;
+	struct rvin_graph_entity *csi = to_rvin_graph_entity(asd);
 
 	mutex_lock(&vin->group->lock);
-	for (i = 0; i < RVIN_CSI_MAX; i++) {
-		if (&vin->group->csi[i].asd == asd) {
-			vin_dbg(vin, "Unbind CSI-2 %s\n", subdev->name);
-			vin->group->csi[i].subdev = NULL;
-			mutex_unlock(&vin->group->lock);
-			return;
-		}
-	}
+	csi->subdev = NULL;
 	mutex_unlock(&vin->group->lock);
-
-	vin_err(vin, "No entity for subdev %s to unbind\n", subdev->name);
 }
 
 static int rvin_group_notify_bound(struct v4l2_async_notifier *notifier,
@@ -709,23 +700,16 @@ static int rvin_group_notify_bound(struct v4l2_async_notifier *notifier,
 				   struct v4l2_async_subdev *asd)
 {
 	struct rvin_dev *vin = notifier_to_vin(notifier);
-	unsigned int i;
+	struct rvin_graph_entity *csi = to_rvin_graph_entity(asd);
 
 	v4l2_set_subdev_hostdata(subdev, vin);
 
 	mutex_lock(&vin->group->lock);
-	for (i = 0; i < RVIN_CSI_MAX; i++) {
-		if (&vin->group->csi[i].asd == asd) {
-			vin_dbg(vin, "Bound CSI-2 %s\n", subdev->name);
-			vin->group->csi[i].subdev = subdev;
-			mutex_unlock(&vin->group->lock);
-			return 0;
-		}
-	}
+	vin_dbg(vin, "Bound CSI-2 %s\n", subdev->name);
+	csi->subdev = subdev;
 	mutex_unlock(&vin->group->lock);
 
-	vin_err(vin, "No entity for subdev %s to bind\n", subdev->name);
-	return -EINVAL;
+	return 0;
 }
 
 static struct device_node *rvin_group_get_csi(struct rvin_dev *vin,
diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
index e7e600fdf566..900c473c3d15 100644
--- a/drivers/media/platform/rcar-vin/rcar-vin.h
+++ b/drivers/media/platform/rcar-vin/rcar-vin.h
@@ -92,6 +92,9 @@ struct rvin_graph_entity {
 	unsigned int sink_pad;
 };
 
+#define to_rvin_graph_entity(asd) \
+	container_of(asd, struct rvin_graph_entity, asd)
+
 struct rvin_group;
 
 
-- 
2.7.4