[PATCH AUTOSEL 5.4 2/2] drm/sti: hdmi: use eld_mutex to protect access to connector->eld

[Sasha Levin <sashal@kernel.org>]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

[ Upstream commit e99c0b517bcd53cf61f998a3c4291333401cb391 ]

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@kernel.org>
Acked-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241206-drm-connector-eld-mutex-v2-9-c9bce1ee8bea@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/sti/sti_hdmi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c
index c5547fedebe30..ce7cc84499f45 100644
--- a/drivers/gpu/drm/sti/sti_hdmi.c
+++ b/drivers/gpu/drm/sti/sti_hdmi.c
@@ -1214,7 +1214,9 @@ static int hdmi_audio_get_eld(struct device *dev, void *data, uint8_t *buf, size
 	struct drm_connector *connector = hdmi->drm_connector;
 
 	DRM_DEBUG_DRIVER("\n");
+	mutex_lock(&connector->eld_mutex);
 	memcpy(buf, connector->eld, min(sizeof(connector->eld), len));
+	mutex_unlock(&connector->eld_mutex);
 
 	return 0;
 }
-- 
2.39.5