drm: Don't leak phys_wc "handles" to userspace
I didn't fix this in the earlier patch -- it would have broken the
build due to the now-deleted garbage in drm_os_linux.h.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index 0190fce..5a4dbb4 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -414,6 +414,15 @@
/* avoid a warning on 64-bit, this casting isn't very nice, but the API is set so too late */
map->handle = (void *)(unsigned long)maplist->user_token;
+
+ /*
+ * It appears that there are no users of this value whatsoever --
+ * drmAddMap just discards it. Let's not encourage its use.
+ * (Keeping drm_addmap_core's returned mtrr value would be wrong --
+ * it's not a real mtrr index anymore.)
+ */
+ map->mtrr = -1;
+
return 0;
}