[PATCH] drm/logicvc: Fix port node reference leak in logicvc_crtc_init()

[Jason Xiang]

of_graph_get_port_by_id() returns the port node with its reference
count incremented; the caller has to drop that reference with
of_node_put() when done. logicvc_crtc_init() stores the node in
crtc->port but never releases it. The core CRTC cleanup
(drm_crtc_cleanup()) does not put crtc->port either, so the reference
is leaked on unbind, and also on any probe error after this point.

Drop the reference with a device-managed action, as done in other
DRM drivers (e.g. arm/malidp, arm/hdlcd). The leak has been present
since the driver was introduced.

Fixes: efeeaefe9be5 ("drm: Add support for the LogiCVC display controller")
Signed-off-by: Jason Xiang <jx@xxxxxxxxxxxxxx>
---
 drivers/gpu/drm/logicvc/logicvc_crtc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/logicvc/logicvc_crtc.c b/drivers/gpu/drm/logicvc/logicvc_crtc.c
index 81e5b80736fa..4de48822ca21 100644
--- a/drivers/gpu/drm/logicvc/logicvc_crtc.c
+++ b/drivers/gpu/drm/logicvc/logicvc_crtc.c
@@ -243,6 +243,11 @@ void logicvc_crtc_vblank_handler(struct logicvc_drm *logicvc)
 	}
 }
 
+static void logicvc_crtc_of_node_put(void *data)
+{
+	of_node_put(data);
+}
+
 int logicvc_crtc_init(struct logicvc_drm *logicvc)
 {
 	struct drm_device *drm_dev = &logicvc->drm_dev;
@@ -274,6 +279,10 @@ int logicvc_crtc_init(struct logicvc_drm *logicvc)
 
 	crtc->drm_crtc.port = of_graph_get_port_by_id(of_node, 1);
 
+	ret = devm_add_action_or_reset(dev, logicvc_crtc_of_node_put, crtc->drm_crtc.port);
+	if (ret)
+		return ret;
+
 	logicvc->crtc = crtc;
 
 	return 0;

base-commit: f0e6f20cb52b14c2c441f04e21cef0c95d498cac
-- 
2.53.0