linux-kernel - [PATCH] drm/kmb: Replace of_node_put() with automatic cleanup handler

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Message-Id: <20240410-kmb_of_node_put-v1-1-4d802add6a89@gmail.com>
Date: Wed, 10 Apr 2024 22:45:43 +0200
From: Javier Carrasco <javier.carrasco.cruz@...il.com>
To: Anitha Chrisanthus <anitha.chrisanthus@...el.com>, 
 Edmund Dea <edmund.j.dea@...el.com>, David Airlie <airlied@...il.com>, 
 Daniel Vetter <daniel@...ll.ch>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 Julia Lawall <julia.lawall@...ia.fr>, 
 Javier Carrasco <javier.carrasco.cruz@...il.com>
Subject: [PATCH] drm/kmb: Replace of_node_put() with automatic cleanup
 handler

Make use of the __free() cleanup handler to automatically free nodes
when they get out of scope.

Suggested-by: Julia Lawall <julia.lawall@...ia.fr>
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
---
The patch is based on the latest linux-next tag (next-20240410).
---
 drivers/gpu/drm/kmb/kmb_drv.c | 13 ++++---------
 drivers/gpu/drm/kmb/kmb_dsi.c | 11 ++++-------
 2 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/kmb/kmb_drv.c b/drivers/gpu/drm/kmb/kmb_drv.c
index 169b83987ce2..1a743840688a 100644
--- a/drivers/gpu/drm/kmb/kmb_drv.c
+++ b/drivers/gpu/drm/kmb/kmb_drv.c
@@ -480,8 +480,8 @@ static int kmb_probe(struct platform_device *pdev)
 	struct device *dev = get_device(&pdev->dev);
 	struct kmb_drm_private *kmb;
 	int ret = 0;
-	struct device_node *dsi_in;
-	struct device_node *dsi_node;
+	struct device_node *dsi_in __free(device_node) =
+		of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
 	struct platform_device *dsi_pdev;
 
 	/* The bridge (ADV 7535) will return -EPROBE_DEFER until it
@@ -491,28 +491,23 @@ static int kmb_probe(struct platform_device *pdev)
 	 *  and then the rest of the driver initialization can proceed
 	 *  afterwards and the bridge can be successfully attached.
 	 */
-	dsi_in = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
 	if (!dsi_in) {
 		DRM_ERROR("Failed to get dsi_in node info from DT");
 		return -EINVAL;
 	}
-	dsi_node = of_graph_get_remote_port_parent(dsi_in);
+	struct device_node *dsi_node __free(device_node) =
+		of_graph_get_remote_port_parent(dsi_in);
 	if (!dsi_node) {
-		of_node_put(dsi_in);
 		DRM_ERROR("Failed to get dsi node from DT\n");
 		return -EINVAL;
 	}
 
 	dsi_pdev = of_find_device_by_node(dsi_node);
 	if (!dsi_pdev) {
-		of_node_put(dsi_in);
-		of_node_put(dsi_node);
 		DRM_ERROR("Failed to get dsi platform device\n");
 		return -EINVAL;
 	}
 
-	of_node_put(dsi_in);
-	of_node_put(dsi_node);
 	ret = kmb_dsi_host_bridge_init(get_device(&dsi_pdev->dev));
 
 	if (ret == -EPROBE_DEFER) {
diff --git a/drivers/gpu/drm/kmb/kmb_dsi.c b/drivers/gpu/drm/kmb/kmb_dsi.c
index cf7cf0b07541..61f02462b778 100644
--- a/drivers/gpu/drm/kmb/kmb_dsi.c
+++ b/drivers/gpu/drm/kmb/kmb_dsi.c
@@ -216,8 +216,6 @@ static const struct mipi_dsi_host_ops kmb_dsi_host_ops = {
 
 int kmb_dsi_host_bridge_init(struct device *dev)
 {
-	struct device_node *encoder_node, *dsi_out;
-
 	/* Create and register MIPI DSI host */
 	if (!dsi_host) {
 		dsi_host = kzalloc(sizeof(*dsi_host), GFP_KERNEL);
@@ -239,21 +237,20 @@ int kmb_dsi_host_bridge_init(struct device *dev)
 	}
 
 	/* Find ADV7535 node and initialize it */
-	dsi_out = of_graph_get_endpoint_by_regs(dev->of_node, 0, 1);
+	struct device_node *dsi_out __free(device_node) =
+		of_graph_get_endpoint_by_regs(dev->of_node, 0, 1);
 	if (!dsi_out) {
 		DRM_ERROR("Failed to get dsi_out node info from DT\n");
 		return -EINVAL;
 	}
-	encoder_node = of_graph_get_remote_port_parent(dsi_out);
+	struct device_node *encoder_node __free(device_node) =
+		of_graph_get_remote_port_parent(dsi_out);
 	if (!encoder_node) {
-		of_node_put(dsi_out);
 		DRM_ERROR("Failed to get bridge info from DT\n");
 		return -EINVAL;
 	}
 	/* Locate drm bridge from the hdmi encoder DT node */
 	adv_bridge = of_drm_find_bridge(encoder_node);
-	of_node_put(dsi_out);
-	of_node_put(encoder_node);
 	if (!adv_bridge) {
 		DRM_DEBUG("Wait for external bridge driver DT\n");
 		return -EPROBE_DEFER;

---
base-commit: 6ebf211bb11dfc004a2ff73a9de5386fa309c430
change-id: 20240410-kmb_of_node_put-aaf1c77d9610

Best regards,
-- 
Javier Carrasco <javier.carrasco.cruz@...il.com>