drm: Preserve the list head in drm_mode_copy

Preserve the destination mode's list head in drm_mode_copy. Just
in case someone decides that it's a good idea to overwrite a mode which
happens to be on some list,

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 09785422e654..69153385c63f 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -789,16 +789,17 @@ EXPORT_SYMBOL(drm_mode_set_crtcinfo);
  * LOCKING:
  * None.
  *
- * Copy an existing mode into another mode, preserving the object id
- * of the destination mode.
+ * Copy an existing mode into another mode, preserving the object id and
+ * list head of the destination mode.
  */
 void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode *src)
 {
         int id = dst->base.id;
+        struct list_head head = dst->head;
 
         *dst = *src;
         dst->base.id = id;
-        INIT_LIST_HEAD(&dst->head);
+        dst->head = head;
 }
 EXPORT_SYMBOL(drm_mode_copy);