diff --git a/src/plugins/platforms/xcb/qxcbbackingstore.cpp b/src/plugins/platforms/xcb/qxcbbackingstore.cpp
index 1e046aa677..979c8142f7 100644
--- a/src/plugins/platforms/xcb/qxcbbackingstore.cpp
+++ b/src/plugins/platforms/xcb/qxcbbackingstore.cpp
@@ -520,16 +520,7 @@ void QXcbShmImage::setClip(const QRegion &region)
         static const uint32_t values[] = { XCB_NONE };
         xcb_change_gc(xcb_connection(), m_gc, mask, values);
     } else {
-        const QVector<QRect> qrects = region.rects();
-        QVector<xcb_rectangle_t> xcb_rects(qrects.size());
-
-        for (int i = 0; i < qrects.size(); i++) {
-            xcb_rects[i].x = qrects[i].x();
-            xcb_rects[i].y = qrects[i].y();
-            xcb_rects[i].width = qrects[i].width();
-            xcb_rects[i].height = qrects[i].height();
-        }
-
+        const auto xcb_rects = qRegionToXcbRectangleList(region);
         xcb_set_clip_rectangles(xcb_connection(),
                                 XCB_CLIP_ORDERING_YX_BANDED,
                                 m_gc,
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 5ea865f74a..e7096fb8f0 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -2776,6 +2776,15 @@ void QXcbWindow::setOpacity(qreal level)
                         (uchar *)&value);
 }
 
+QVector<xcb_rectangle_t> qRegionToXcbRectangleList(const QRegion &region)
+{
+    QVector<xcb_rectangle_t> rects;
+    rects.reserve(region.rectCount());
+    for (const QRect &r : region)
+        rects.push_back(qRectToXCBRectangle(r));
+    return rects;
+}
+
 void QXcbWindow::setMask(const QRegion &region)
 {
     if (!connection()->hasXShape())
@@ -2784,10 +2793,7 @@ void QXcbWindow::setMask(const QRegion &region)
         xcb_shape_mask(connection()->xcb_connection(), XCB_SHAPE_SO_SET,
                        XCB_SHAPE_SK_BOUNDING, xcb_window(), 0, 0, XCB_NONE);
     } else {
-        QVector<xcb_rectangle_t> rects;
-        rects.reserve(region.rectCount());
-        for (const QRect &r : region)
-            rects.push_back(qRectToXCBRectangle(r));
+        const auto rects = qRegionToXcbRectangleList(region);
         xcb_shape_rectangles(connection()->xcb_connection(), XCB_SHAPE_SO_SET,
                              XCB_SHAPE_SK_BOUNDING, XCB_CLIP_ORDERING_UNSORTED,
                              xcb_window(), 0, 0, rects.size(), &rects[0]);
diff --git a/src/plugins/platforms/xcb/qxcbwindow.h b/src/plugins/platforms/xcb/qxcbwindow.h
index b89dddf72f..638ab26cea 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.h
+++ b/src/plugins/platforms/xcb/qxcbwindow.h
@@ -296,6 +296,8 @@ protected:
     void create() override {} // No-op
 };
 
+QVector<xcb_rectangle_t> qRegionToXcbRectangleList(const QRegion &region);
+
 QT_END_NAMESPACE
 
 Q_DECLARE_METATYPE(QXcbWindow*)