drm: allow property validation for refcnted props
We can already have object properties, which technically can be fb's.
Switch the property validation logic over to a get/put style interface
so it can take a ref to refcnt'd objects, and then drop that ref after
the driver has a chance to take it's own ref.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 5213da4..5ee4b88 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -4193,12 +4193,22 @@
}
EXPORT_SYMBOL(drm_mode_connector_update_edid_property);
-static bool drm_property_change_is_valid(struct drm_property *property,
- uint64_t value)
+/* Some properties could refer to dynamic refcnt'd objects, or things that
+ * need special locking to handle lifetime issues (ie. to ensure the prop
+ * value doesn't become invalid part way through the property update due to
+ * race). The value returned by reference via 'obj' should be passed back
+ * to drm_property_change_valid_put() after the property is set (and the
+ * object to which the property is attached has a chance to take it's own
+ * reference).
+ */
+static bool drm_property_change_valid_get(struct drm_property *property,
+ uint64_t value, struct drm_mode_object **ref)
{
if (property->flags & DRM_MODE_PROP_IMMUTABLE)
return false;
+ *ref = NULL;
+
if (drm_property_type_is(property, DRM_MODE_PROP_RANGE)) {
if (value < property->values[0] || value > property->values[1])
return false;
@@ -4219,19 +4229,23 @@
/* Only the driver knows */
return true;
} else if (drm_property_type_is(property, DRM_MODE_PROP_OBJECT)) {
- struct drm_mode_object *obj;
/* a zero value for an object property translates to null: */
if (value == 0)
return true;
- /*
- * NOTE: use _object_find() directly to bypass restriction on
- * looking up refcnt'd objects (ie. fb's). For a refcnt'd
- * object this could race against object finalization, so it
- * simply tells us that the object *was* valid. Which is good
- * enough.
- */
- obj = _object_find(property->dev, value, property->values[0]);
- return obj != NULL;
+
+ /* handle refcnt'd objects specially: */
+ if (property->values[0] == DRM_MODE_OBJECT_FB) {
+ struct drm_framebuffer *fb;
+ fb = drm_framebuffer_lookup(property->dev, value);
+ if (fb) {
+ *ref = &fb->base;
+ return true;
+ } else {
+ return false;
+ }
+ } else {
+ return _object_find(property->dev, value, property->values[0]) != NULL;
+ }
} else {
int i;
for (i = 0; i < property->num_values; i++)
@@ -4241,6 +4255,18 @@
}
}
+static void drm_property_change_valid_put(struct drm_property *property,
+ struct drm_mode_object *ref)
+{
+ if (!ref)
+ return;
+
+ if (drm_property_type_is(property, DRM_MODE_PROP_OBJECT)) {
+ if (property->values[0] == DRM_MODE_OBJECT_FB)
+ drm_framebuffer_unreference(obj_to_fb(ref));
+ }
+}
+
/**
* drm_mode_connector_property_set_ioctl - set the current value of a connector property
* @dev: DRM device
@@ -4429,8 +4455,8 @@
struct drm_mode_object *arg_obj;
struct drm_mode_object *prop_obj;
struct drm_property *property;
- int ret = -EINVAL;
- int i;
+ int i, ret = -EINVAL;
+ struct drm_mode_object *ref;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EINVAL;
@@ -4460,7 +4486,7 @@
}
property = obj_to_property(prop_obj);
- if (!drm_property_change_is_valid(property, arg->value))
+ if (!drm_property_change_valid_get(property, arg->value, &ref))
goto out;
switch (arg_obj->type) {
@@ -4477,6 +4503,8 @@
break;
}
+ drm_property_change_valid_put(property, ref);
+
out:
drm_modeset_unlock_all(dev);
return ret;