drm: Use drm_mode_init() for on-stack modes

Initialize on-stack modes with drm_mode_init() to guarantee
no stack garbage in the list head, or that we aren't copying
over another mode's list head.

Based on the following cocci script, with manual fixups:
@decl@
identifier M;
expression E;
@@
- struct drm_display_mode M = E;
+ struct drm_display_mode M;

@@
identifier decl.M;
expression decl.E;
statement S, S1;
@@
struct drm_display_mode M;
... when != S
+ drm_mode_init(&M, &E);
+
S1

@@
expression decl.E;
@@
- &*E
+ E

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220218100403.7028-22-ville.syrjala@linux.intel.com
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index bff917531f33..a34aa009725f 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -297,8 +297,8 @@ bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 		return false;
 	}
 
-	saved_mode = crtc->mode;
-	saved_hwmode = crtc->hwmode;
+	drm_mode_init(&saved_mode, &crtc->mode);
+	drm_mode_init(&saved_hwmode, &crtc->hwmode);
 	saved_x = crtc->x;
 	saved_y = crtc->y;
 
@@ -411,8 +411,8 @@ done:
 	drm_mode_destroy(dev, adjusted_mode);
 	if (!ret) {
 		crtc->enabled = saved_enabled;
-		crtc->mode = saved_mode;
-		crtc->hwmode = saved_hwmode;
+		drm_mode_copy(&crtc->mode, &saved_mode);
+		drm_mode_copy(&crtc->hwmode, &saved_hwmode);
 		crtc->x = saved_x;
 		crtc->y = saved_y;
 	}