From 147c4b09bd8bd2fc9bb5592c5f09b3691321b22a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Fri, 18 Feb 2022 12:03:58 +0200
Subject: drm/vc4: Use drm_mode_copy()
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Git-commit: d8a8cf8242ebc1f2b291d70abf7949b314bc2e01
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
struct drm_display_mode embeds a list head, so overwriting
the full struct with another one will corrupt the list
(if the destination mode is on a list). Use drm_mode_copy()
instead which explicitly preserves the list head of
the destination mode.
Even if we know the destination mode is not on any list
using drm_mode_copy() seems decent as it sets a good
example. Bad examples of not using it might eventually
get copied into code where preserving the list head
actually matters.
Obviously one case not covered here is when the mode
itself is embedded in a larger structure and the whole
structure is copied. But if we are careful when copying
into modes embedded in structures I think we can be a
little more reassured that bogus list heads haven't been
propagated in.
@is_mode_copy@
@@
drm_mode_copy(...)
{
...
}
@depends on !is_mode_copy@
struct drm_display_mode *mode;
expression E, S;
@@
(
- *mode = E
+ drm_mode_copy(mode, &E)
|
- memcpy(mode, E, S)
+ drm_mode_copy(mode, E)
)
@depends on !is_mode_copy@
struct drm_display_mode mode;
expression E;
@@
(
- mode = E
+ drm_mode_copy(&mode, &E)
|
- memcpy(&mode, E, S)
+ drm_mode_copy(&mode, E)
)
@@
struct drm_display_mode *mode;
@@
- &*mode
+ mode
Cc: Emma Anholt <emma@anholt.net>
Cc: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220218100403.7028-18-ville.syrjala@linux.intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 5ac3216f2d4a..6c58b0fd13fb 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1234,9 +1234,8 @@ static void vc4_hdmi_encoder_atomic_mode_set(struct drm_encoder *encoder,
struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
mutex_lock(&vc4_hdmi->mutex);
- memcpy(&vc4_hdmi->saved_adjusted_mode,
- &crtc_state->adjusted_mode,
- sizeof(vc4_hdmi->saved_adjusted_mode));
+ drm_mode_copy(&vc4_hdmi->saved_adjusted_mode,
+ &crtc_state->adjusted_mode);
mutex_unlock(&vc4_hdmi->mutex);
}
--
2.38.1