drm: Add drm_rect_equals()

drm_rect_equals() tells whether two drm_rects are equal.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: NDave Airlie <airlied@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

include/drm/drm_rect.h

@@ -124,6 +124,21 @@ static inline bool drm_rect_visible(const struct drm_rect *r)
 	return drm_rect_width(r) > 0 && drm_rect_height(r) > 0;
 }
 
+/**
+ * drm_rect_equals - determine if two rectangles are equal
+ * @r1: first rectangle
+ * @r2: second rectangle
+ *
+ * RETURNS:
+ * %true if the rectangles are equal, %false otherwise.
+ */
+static inline bool drm_rect_equals(const struct drm_rect *r1,
+				   const struct drm_rect *r2)
+{
+	return r1->x1 == r2->x1 && r1->x2 == r2->x2 &&
+		r1->y1 == r2->y1 && r1->y2 == r2->y2;
+}
+
 bool drm_rect_intersect(struct drm_rect *r, const struct drm_rect *clip);
 bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
 			  const struct drm_rect *clip,