On 18.02.2022 11:03, Ville Syrjala wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
Add a variant of drm_mode_copy() that explicitly clears out the list head of the destination mode. Helpful to guarantee we don't have stack garbage left in there for on-stack modes.
Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/drm_modes.c | 17 +++++++++++++++++ include/drm/drm_modes.h | 2 ++ 2 files changed, 19 insertions(+)
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c index 96b13e36293c..40d4ce4a1da4 100644 --- a/drivers/gpu/drm/drm_modes.c +++ b/drivers/gpu/drm/drm_modes.c @@ -892,6 +892,23 @@ void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode * } EXPORT_SYMBOL(drm_mode_copy);
+/**
- drm_mode_init - initialize the mode from another mode
- @dst: mode to overwrite
- @src: mode to copy
- Copy an existing mode into another mode, zeroing the
- list head of the destination mode. Typically used
- to guarantee the list head is not left with stack
- garbage in on-stack modes.
- */
+void drm_mode_init(struct drm_display_mode *dst, const struct drm_display_mode *src) +{
- memset(dst, 0, sizeof(*dst));
Why not just clear the list head? Or maybe poison it? It would be more cleaner.
I wonder why there is no such helper in list.h.
Regards Andrzej
- drm_mode_copy(dst, src);
+} +EXPORT_SYMBOL(drm_mode_init);
- /**
- drm_mode_duplicate - allocate and duplicate an existing mode
- @dev: drm_device to allocate the duplicated mode for
diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h index 29ba4adf0c53..e6e5a588fab1 100644 --- a/include/drm/drm_modes.h +++ b/include/drm/drm_modes.h @@ -484,6 +484,8 @@ void drm_mode_set_crtcinfo(struct drm_display_mode *p, int adjust_flags); void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode *src); +void drm_mode_init(struct drm_display_mode *dst,
const struct drm_display_mode *src);