drm/amdgpu: Use drm_mode_copy()

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: Alex Deucher <alexander.deucher@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
index fa20261aa9285de650e20d1eaa0e07f842331cf6..673078faa27a7d29a0758fe66d5f8edcb7626d0e 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -626,7 +626,7 @@ amdgpu_connector_fixup_lcd_native_mode(struct drm_encoder *encoder,
                if (mode->type & DRM_MODE_TYPE_PREFERRED) {
                        if (mode->hdisplay != native_mode->hdisplay ||
                            mode->vdisplay != native_mode->vdisplay)
-                               memcpy(native_mode, mode, sizeof(*mode));
+                               drm_mode_copy(native_mode, mode);
                }
        }
 
@@ -635,7 +635,7 @@ amdgpu_connector_fixup_lcd_native_mode(struct drm_encoder *encoder,
                list_for_each_entry_safe(mode, t, &connector->probed_modes, head) {
                        if (mode->hdisplay == native_mode->hdisplay &&
                            mode->vdisplay == native_mode->vdisplay) {
-                               *native_mode = *mode;
+                               drm_mode_copy(native_mode, mode);
                                drm_mode_set_crtcinfo(native_mode, CRTC_INTERLACE_HALVE_V);
                                DRM_DEBUG_KMS("Determined LVDS native mode details from EDID\n");
                                break;

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 234af77915aa6724dfa2ffcdc99e4472cb073965..b30656959fd862324591d3d3ad73ff465ab642b6 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6360,7 +6360,7 @@ get_highest_refresh_rate_mode(struct amdgpu_dm_connector *aconnector,
                }
        }
 
-       aconnector->freesync_vid_base = *m_pref;
+       drm_mode_copy(&aconnector->freesync_vid_base, m_pref);
        return m_pref;
 }
 
@@ -6473,8 +6473,8 @@ create_stream_for_sink(struct amdgpu_dm_connector *aconnector,
                recalculate_timing = is_freesync_video_mode(&mode, aconnector);
                if (recalculate_timing) {
                        freesync_mode = get_highest_refresh_rate_mode(aconnector, false);
-                       saved_mode = mode;
-                       mode = *freesync_mode;
+                       drm_mode_copy(&saved_mode, &mode);
+                       drm_mode_copy(&mode, freesync_mode);
                } else {
                        decide_crtc_timing_for_drm_display_mode(
                                &mode, preferred_mode, scale);