linux-kernel - [PATCH v2 03/10] drm/bridge: ite-it66121: use eld_mutex to protect access to connector->eld

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Message-Id: <20241206-drm-connector-eld-mutex-v2-3-c9bce1ee8bea@linaro.org>
Date: Fri, 06 Dec 2024 11:43:06 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: 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>, 
 Harry Wentland <harry.wentland@....com>, Leo Li <sunpeng.li@....com>, 
 Rodrigo Siqueira <Rodrigo.Siqueira@....com>, 
 Alex Deucher <alexander.deucher@....com>, 
 Christian König <christian.koenig@....com>, 
 Xinhui Pan <Xinhui.Pan@....com>, 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>, 
 Phong LE <ple@...libre.com>, Inki Dae <inki.dae@...sung.com>, 
 Seung-Woo Kim <sw0312.kim@...sung.com>, 
 Kyungmin Park <kyungmin.park@...sung.com>, 
 Krzysztof Kozlowski <krzk@...nel.org>, 
 Alim Akhtar <alim.akhtar@...sung.com>, 
 Jani Nikula <jani.nikula@...ux.intel.com>, 
 Rodrigo Vivi <rodrigo.vivi@...el.com>, 
 Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>, 
 Tvrtko Ursulin <tursulin@...ulin.net>, Rob Clark <robdclark@...il.com>, 
 Abhinav Kumar <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>, 
 Marijn Suijten <marijn.suijten@...ainline.org>, 
 Alain Volmat <alain.volmat@...s.st.com>, 
 Raphael Gallais-Pou <rgallaispou@...il.com>, 
 Dave Stevenson <dave.stevenson@...pberrypi.com>, 
 Maíra Canal <mcanal@...lia.com>, 
 Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 amd-gfx@...ts.freedesktop.org, linux-arm-kernel@...ts.infradead.org, 
 linux-samsung-soc@...r.kernel.org, intel-gfx@...ts.freedesktop.org, 
 intel-xe@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org, 
 freedreno@...ts.freedesktop.org
Subject: [PATCH v2 03/10] drm/bridge: ite-it66121: use eld_mutex to protect
 access to connector->eld

Reading access to connector->eld can happen at the same time the
drm_edid_to_eld() updates the data. Take the newly added eld_mutex in
order to protect connector->eld from concurrent access.

Reviewed-by: Maxime Ripard <mripard@...nel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
 drivers/gpu/drm/bridge/ite-it66121.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
index 35ae3f0e8f51f768229e055a086b53a419ffcd9f..940083e5d2ddbfc56f14e2bdc6ddd0b9dd50b1f8 100644
--- a/drivers/gpu/drm/bridge/ite-it66121.c
+++ b/drivers/gpu/drm/bridge/ite-it66121.c
@@ -1450,8 +1450,10 @@ static int it66121_audio_get_eld(struct device *dev, void *data,
 		dev_dbg(dev, "No connector present, passing empty EDID data");
 		memset(buf, 0, len);
 	} else {
+		mutex_lock(&ctx->connector->eld_mutex);
 		memcpy(buf, ctx->connector->eld,
 		       min(sizeof(ctx->connector->eld), len));
+		mutex_unlock(&ctx->connector->eld_mutex);
 	}
 	mutex_unlock(&ctx->lock);
 

-- 
2.39.5