diff --git a/src/corelib/io/qfiledevice_p.h b/src/corelib/io/qfiledevice_p.h
index aef3fca811..9adba680d7 100644
--- a/src/corelib/io/qfiledevice_p.h
+++ b/src/corelib/io/qfiledevice_p.h
@@ -54,6 +54,10 @@
 #include "private/qiodevice_p.h"
 
 #include <memory>
+#ifdef Q_OS_UNIX
+#  include <sys/types.h> // for mode_t
+#  include <sys/stat.h>  // for mode_t constants
+#endif
 
 QT_BEGIN_NAMESPACE
 
@@ -98,6 +102,36 @@ inline bool QFileDevicePrivate::ensureFlushed() const
     return true;
 }
 
+#ifdef Q_OS_UNIX
+namespace QtPrivate {
+
+constexpr mode_t toMode_t(QFileDevice::Permissions permissions)
+{
+    mode_t mode = 0;
+    if (permissions & (QFileDevice::ReadOwner | QFileDevice::ReadUser))
+        mode |= S_IRUSR;
+    if (permissions & (QFileDevice::WriteOwner | QFileDevice::WriteUser))
+        mode |= S_IWUSR;
+    if (permissions & (QFileDevice::ExeOwner | QFileDevice::ExeUser))
+        mode |= S_IXUSR;
+    if (permissions & QFileDevice::ReadGroup)
+        mode |= S_IRGRP;
+    if (permissions & QFileDevice::WriteGroup)
+        mode |= S_IWGRP;
+    if (permissions & QFileDevice::ExeGroup)
+        mode |= S_IXGRP;
+    if (permissions & QFileDevice::ReadOther)
+        mode |= S_IROTH;
+    if (permissions & QFileDevice::WriteOther)
+        mode |= S_IWOTH;
+    if (permissions & QFileDevice::ExeOther)
+        mode |= S_IXOTH;
+    return mode;
+}
+
+} // namespace QtPrivate
+#endif // Q_OS_UNIX
+
 QT_END_NAMESPACE
 
 #endif // QFILEDEVICE_P_H
diff --git a/src/corelib/io/qfilesystemengine_unix.cpp b/src/corelib/io/qfilesystemengine_unix.cpp
index 054e9ed2fe..8c2df84b72 100644
--- a/src/corelib/io/qfilesystemengine_unix.cpp
+++ b/src/corelib/io/qfilesystemengine_unix.cpp
@@ -46,6 +46,7 @@
 
 #include <QtCore/qoperatingsystemversion.h>
 #include <QtCore/private/qcore_unix_p.h>
+#include <QtCore/private/qfiledevice_p.h>
 #include <QtCore/qvarlengtharray.h>
 #ifndef QT_BOOTSTRAPPED
 # include <QtCore/qstandardpaths.h>
@@ -53,8 +54,6 @@
 
 #include <pwd.h>
 #include <stdlib.h> // for realpath()
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <unistd.h>
 #include <stdio.h>
 #include <errno.h>
@@ -1527,36 +1526,12 @@ bool QFileSystemEngine::removeFile(const QFileSystemEntry &entry, QSystemError &
 
 }
 
-static mode_t toMode_t(QFile::Permissions permissions)
-{
-    mode_t mode = 0;
-    if (permissions & (QFile::ReadOwner | QFile::ReadUser))
-        mode |= S_IRUSR;
-    if (permissions & (QFile::WriteOwner | QFile::WriteUser))
-        mode |= S_IWUSR;
-    if (permissions & (QFile::ExeOwner | QFile::ExeUser))
-        mode |= S_IXUSR;
-    if (permissions & QFile::ReadGroup)
-        mode |= S_IRGRP;
-    if (permissions & QFile::WriteGroup)
-        mode |= S_IWGRP;
-    if (permissions & QFile::ExeGroup)
-        mode |= S_IXGRP;
-    if (permissions & QFile::ReadOther)
-        mode |= S_IROTH;
-    if (permissions & QFile::WriteOther)
-        mode |= S_IWOTH;
-    if (permissions & QFile::ExeOther)
-        mode |= S_IXOTH;
-    return mode;
-}
-
 //static
 bool QFileSystemEngine::setPermissions(const QFileSystemEntry &entry, QFile::Permissions permissions, QSystemError &error, QFileSystemMetaData *data)
 {
     Q_CHECK_FILE_NAME(entry, false);
 
-    mode_t mode = toMode_t(permissions);
+    mode_t mode = QtPrivate::toMode_t(permissions);
     bool success = ::chmod(entry.nativeFilePath().constData(), mode) == 0;
     if (success && data) {
         data->entryFlags &= ~QFileSystemMetaData::Permissions;
@@ -1571,7 +1546,7 @@ bool QFileSystemEngine::setPermissions(const QFileSystemEntry &entry, QFile::Per
 //static
 bool QFileSystemEngine::setPermissions(int fd, QFile::Permissions permissions, QSystemError &error, QFileSystemMetaData *data)
 {
-    mode_t mode = toMode_t(permissions);
+    mode_t mode = QtPrivate::toMode_t(permissions);
 
     bool success = ::fchmod(fd, mode) == 0;
     if (success && data) {