linux-kernel - [PATCH v5 06/10] drm/bridge: ti-sn65dsi83: use dynamic lifetime management

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Message-Id: <20241231-hotplug-drm-bridge-v5-6-173065a1ece1@bootlin.com>
Date: Tue, 31 Dec 2024 11:40:00 +0100
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: Simona Vetter <simona@...ll.ch>, Inki Dae <inki.dae@...sung.com>, 
 Jagan Teki <jagan@...rulasolutions.com>, 
 Marek Szyprowski <m.szyprowski@...sung.com>, 
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Daniel Thompson <danielt@...nel.org>, 
 Andrzej Hajda <andrzej.hajda@...el.com>, Jonathan Corbet <corbet@....net>
Cc: Paul Kocialkowski <contact@...lk.fr>, 
 Maxime Ripard <mripard@...nel.org>, 
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
 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>, 
 Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
 Hervé Codina <herve.codina@...tlin.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
 linux-doc@...r.kernel.org, 
 Paul Kocialkowski <paul.kocialkowski@...tlin.com>, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v5 06/10] drm/bridge: ti-sn65dsi83: use dynamic lifetime
 management

With proper use of drm_bridge_get() and _put(), this allows the bridge to
be removable without dangling pointers and use-after-free.

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

---

This patch was added in v5.
---
 drivers/gpu/drm/bridge/ti-sn65dsi83.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
index 246fece303bc0ae9fb2eaa9c6218ce2ecd550f3b..df3ec39817f32879f9aab65812b6e7f4723f72fb 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c
@@ -267,6 +267,11 @@ static void sn65dsi83_detach(struct drm_bridge *bridge)
 	ctx->dsi = NULL;
 }
 
+static void sn65dsi83_destroy(struct drm_bridge *bridge)
+{
+	kfree(bridge_to_sn65dsi83(bridge));
+}
+
 static u8 sn65dsi83_get_lvds_range(struct sn65dsi83 *ctx,
 				   const struct drm_display_mode *mode)
 {
@@ -695,6 +700,7 @@ sn65dsi83_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
 static const struct drm_bridge_funcs sn65dsi83_funcs = {
 	.attach			= sn65dsi83_attach,
 	.detach			= sn65dsi83_detach,
+	.destroy		= sn65dsi83_destroy,
 	.atomic_enable		= sn65dsi83_atomic_enable,
 	.atomic_pre_enable	= sn65dsi83_atomic_pre_enable,
 	.atomic_disable		= sn65dsi83_atomic_disable,
@@ -813,10 +819,14 @@ static int sn65dsi83_probe(struct i2c_client *client)
 	struct sn65dsi83 *ctx;
 	int ret;
 
-	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;
 
+	ret = drm_bridge_init(dev, &ctx->bridge, &sn65dsi83_funcs);
+	if (ret)
+		return ret;
+
 	ctx->dev = dev;
 	INIT_WORK(&ctx->reset_work, sn65dsi83_reset_work);
 	INIT_DELAYED_WORK(&ctx->monitor_work, sn65dsi83_monitor_work);
@@ -855,7 +865,6 @@ static int sn65dsi83_probe(struct i2c_client *client)
 	dev_set_drvdata(dev, ctx);
 	i2c_set_clientdata(client, ctx);
 
-	ctx->bridge.funcs = &sn65dsi83_funcs;
 	ctx->bridge.of_node = dev->of_node;
 	ctx->bridge.pre_enable_prev_first = true;
 	drm_bridge_add(&ctx->bridge);

-- 
2.34.1