[PATCH] drm/vc4: remove all usages of of_node_put()

[Amer Al Shanawany]

Use the scope-based cleanup feature to clean up 'struct device_node *'
when they go out of scope, and remove all instances of of_node_put()
within the same scope, to simplify function exit and avoid potential
memory leaks.

Suggested-by: Julia Lawall <julia.lawall at inria.fr>
Signed-off-by: Amer Al Shanawany <amer.shanawany at gmail.com>
---
 drivers/gpu/drm/vc4/vc4_drv.c  | 14 ++++++--------
 drivers/gpu/drm/vc4/vc4_hdmi.c |  4 +---
 drivers/gpu/drm/vc4/vc4_hvs.c  |  4 +---
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index c133e96b8aca..bb0bb052e595 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -289,7 +289,6 @@ static int vc4_drm_bind(struct device *dev)
 	struct rpi_firmware *firmware = NULL;
 	struct drm_device *drm;
 	struct vc4_dev *vc4;
-	struct device_node *node;
 	struct drm_crtc *crtc;
 	bool is_vc5;
 	int ret = 0;
@@ -302,11 +301,10 @@ static int vc4_drm_bind(struct device *dev)
 	else
 		driver = &vc4_drm_driver;
 
-	node = of_find_matching_node_and_match(NULL, vc4_dma_range_matches,
-					       NULL);
+	struct device_node *node __free(device_node) =
+		of_find_matching_node_and_match(NULL, vc4_dma_range_matches, NULL);
 	if (node) {
 		ret = of_dma_configure(dev, node, true);
-		of_node_put(node);
 
 		if (ret)
 			return ret;
@@ -341,10 +339,10 @@ static int vc4_drm_bind(struct device *dev)
 			goto err;
 	}
 
-	node = of_find_compatible_node(NULL, NULL, "raspberrypi,bcm2835-firmware");
-	if (node) {
-		firmware = rpi_firmware_get(node);
-		of_node_put(node);
+	struct device_node *np __free(device_node) =
+		of_find_compatible_node(NULL, NULL, "raspberrypi,bcm2835-firmware");
+	if (np) {
+		firmware = rpi_firmware_get(np);
 
 		if (!firmware) {
 			ret = -EPROBE_DEFER;
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index d30f8e8e8967..915e8da3f41a 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -3661,7 +3661,6 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 	struct drm_device *drm = dev_get_drvdata(master);
 	struct vc4_hdmi *vc4_hdmi;
 	struct drm_encoder *encoder;
-	struct device_node *ddc_node;
 	int ret;
 
 	vc4_hdmi = drmm_kzalloc(drm, sizeof(*vc4_hdmi), GFP_KERNEL);
@@ -3699,14 +3698,13 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 	if (ret)
 		return ret;
 
-	ddc_node = of_parse_phandle(dev->of_node, "ddc", 0);
+	struct device_node *ddc_node __free(device_node) = of_parse_phandle(dev->of_node, "ddc", 0);
 	if (!ddc_node) {
 		DRM_ERROR("Failed to find ddc node in device tree\n");
 		return -ENODEV;
 	}
 
 	vc4_hdmi->ddc = of_find_i2c_adapter_by_node(ddc_node);
-	of_node_put(ddc_node);
 	if (!vc4_hdmi->ddc) {
 		DRM_DEBUG("Failed to get ddc i2c adapter by node\n");
 		return -EPROBE_DEFER;
diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index 04af672caacb..6e3613e06e09 100644
--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -845,15 +845,13 @@ static int vc4_hvs_bind(struct device *dev, struct device *master, void *data)
 
 	if (vc4->is_vc5) {
 		struct rpi_firmware *firmware;
-		struct device_node *node;
+		struct device_node *node __free(device_node) = rpi_firmware_find_node();
 		unsigned int max_rate;
 
-		node = rpi_firmware_find_node();
 		if (!node)
 			return -EINVAL;
 
 		firmware = rpi_firmware_get(node);
-		of_node_put(node);
 		if (!firmware)
 			return -EPROBE_DEFER;
 
-- 
2.34.1