linux-kernel - [PATCH v2 04/26] drm/bridge: make of_drm_find_bridge() a wrapper of of_drm_get

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Message-Id: <20251128-drm-bridge-alloc-getput-drm_of_find_bridge-v2-4-88f8a107eca2@bootlin.com>
Date: Fri, 28 Nov 2025 17:50:14 +0100
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
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 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, 
 Adrien Grassein <adrien.grassein@...il.com>, 
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Cc: Hui Pu <Hui.Pu@...ealthcare.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 Louis Chauvet <louis.chauvet@...tlin.com>, dri-devel@...ts.freedesktop.org, 
 linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org, 
 imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
 linux-renesas-soc@...r.kernel.org, linux-amlogic@...ts.infradead.org, 
 linux-mediatek@...ts.infradead.org, linux-samsung-soc@...r.kernel.org, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v2 04/26] drm/bridge: make of_drm_find_bridge() a wrapper
 of of_drm_get_bridge()

of_drm_find_bridge() is identical to of_drm_get_bridge() except it does
not increment the refcount. Rewrite it as a wrapper and put the bridge
being returned so the behaviour is still the same.

Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>

---

Changed in v2:
- Added comment to document why we put the reference
---
 drivers/gpu/drm/drm_bridge.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 21a84715d221..9b7e3f859973 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1467,19 +1467,17 @@ EXPORT_SYMBOL(of_drm_get_bridge);
  */
 struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 {
-	struct drm_bridge *bridge;
-
-	mutex_lock(&bridge_lock);
+	struct drm_bridge *bridge = of_drm_get_bridge(np);
 
-	list_for_each_entry(bridge, &bridge_list, list) {
-		if (bridge->of_node == np) {
-			mutex_unlock(&bridge_lock);
-			return bridge;
-		}
-	}
+	/**
+	 * We need to emulate the original semantics of
+	 * of_drm_find_bridge(), which was not getting any bridge
+	 * reference. Being now based on of_drm_get_bridge() which gets a
+	 * reference, put it before returning.
+	 */
+	drm_bridge_put(bridge);
 
-	mutex_unlock(&bridge_lock);
-	return NULL;
+	return bridge;
 }
 EXPORT_SYMBOL(of_drm_find_bridge);
 #endif

-- 
2.51.1