linux-kernel - [PATCH v7 11/11] drm/bridge: samsung-dsim: use dynamic lifetime management

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Message-Id: <20250314-drm-bridge-refcount-v7-11-152571f8c694@bootlin.com>
Date: Fri, 14 Mar 2025 11:31:24 +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>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Marek Vasut <marex@...x.de>, Stefan Agner <stefan@...er.ch>, 
 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Inki Dae <inki.dae@...sung.com>, 
 Jagan Teki <jagan@...rulasolutions.com>, 
 Marek Szyprowski <m.szyprowski@...sung.com>
Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 Anusha Srivatsa <asrivats@...hat.com>, 
 Paul Kocialkowski <paulk@...-base.io>, Dmitry Baryshkov <lumag@...nel.org>, 
 Hervé Codina <herve.codina@...tlin.com>, 
 Hui Pu <Hui.Pu@...ealthcare.com>, dri-devel@...ts.freedesktop.org, 
 linux-kernel@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v7 11/11] drm/bridge: samsung-dsim: use dynamic lifetime
 management

Allow this bridge to be removable without dangling pointers and
use-after-free, together with proper use of drm_bridge_get() and _put() by
consumers.

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

---

This patch was added in v7.
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 54de6ed2fae81bc13301a6b1ee8f38183a3118b6..3d41db7a0ceeddccc1a89a2ff1f38fe10ec6acfe 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1935,9 +1935,9 @@ int samsung_dsim_probe(struct platform_device *pdev)
 	struct samsung_dsim *dsi;
 	int ret, i;
 
-	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
-	if (!dsi)
-		return -ENOMEM;
+	dsi = devm_drm_bridge_alloc(dev, struct samsung_dsim, bridge, &samsung_dsim_bridge_funcs);
+	if (IS_ERR(dsi))
+		return PTR_ERR(dsi);
 
 	init_completion(&dsi->completed);
 	spin_lock_init(&dsi->transfer_lock);
@@ -2007,7 +2007,6 @@ int samsung_dsim_probe(struct platform_device *pdev)
 
 	pm_runtime_enable(dev);
 
-	dsi->bridge.funcs = &samsung_dsim_bridge_funcs;
 	dsi->bridge.of_node = dev->of_node;
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 

-- 
2.48.1