diff --git a/src/corelib/serialization/qdatastream.cpp b/src/corelib/serialization/qdatastream.cpp
index 5be4e734c67..f1f45895aa9 100644
--- a/src/corelib/serialization/qdatastream.cpp
+++ b/src/corelib/serialization/qdatastream.cpp
@@ -258,7 +258,7 @@ constexpr quint32 QDataStream::ExtendedSize;
         return retVal;
 
 #define CHECK_STREAM_TRANSACTION_PRECOND(retVal) \
-    if (!d || d->transactionDepth == 0) { \
+    if (transactionDepth == 0) { \
         qWarning("QDataStream: No transaction in progress"); \
         return retVal; \
     }
@@ -623,10 +623,7 @@ void QDataStream::startTransaction()
 {
     CHECK_STREAM_PRECOND(Q_VOID)
 
-    if (!d)
-        d.reset(new QDataStreamPrivate());
-
-    if (++d->transactionDepth == 1) {
+    if (++transactionDepth == 1) {
         dev->startTransaction();
         resetStatus();
     }
@@ -655,7 +652,7 @@ void QDataStream::startTransaction()
 bool QDataStream::commitTransaction()
 {
     CHECK_STREAM_TRANSACTION_PRECOND(false)
-    if (--d->transactionDepth == 0) {
+    if (--transactionDepth == 0) {
         CHECK_STREAM_PRECOND(false)
 
         if (q_status == ReadPastEnd) {
@@ -695,7 +692,7 @@ void QDataStream::rollbackTransaction()
     setStatus(ReadPastEnd);
 
     CHECK_STREAM_TRANSACTION_PRECOND(Q_VOID)
-    if (--d->transactionDepth != 0)
+    if (--transactionDepth != 0)
         return;
 
     CHECK_STREAM_PRECOND(Q_VOID)
@@ -731,7 +728,7 @@ void QDataStream::abortTransaction()
     q_status = ReadCorruptData;
 
     CHECK_STREAM_TRANSACTION_PRECOND(Q_VOID)
-    if (--d->transactionDepth != 0)
+    if (--transactionDepth != 0)
         return;
 
     CHECK_STREAM_PRECOND(Q_VOID)
diff --git a/src/corelib/serialization/qdatastream.h b/src/corelib/serialization/qdatastream.h
index b4be27f4742..27694aacc38 100644
--- a/src/corelib/serialization/qdatastream.h
+++ b/src/corelib/serialization/qdatastream.h
@@ -220,9 +220,11 @@ private:
     bool owndev;
     bool noswap;
     quint8 fpPrecision = QDataStream::DoublePrecision;
+    quint8 q_status;
     ByteOrder byteorder;
     int ver;
-    Status q_status;
+    quint16 transactionDepth = 0;
+
 #if QT_CORE_REMOVED_SINCE(6, 7)
     int readBlock(char *data, int len);
 #endif
@@ -426,7 +428,7 @@ inline QIODevice *QDataStream::device() const
 #if QT_CORE_INLINE_IMPL_SINCE(6, 8)
 QDataStream::Status QDataStream::status() const
 {
-    return q_status;
+    return Status(q_status);
 }
 
 QDataStream::FloatingPointPrecision QDataStream::floatingPointPrecision() const
diff --git a/src/corelib/serialization/qdatastream_p.h b/src/corelib/serialization/qdatastream_p.h
index 4600fa64d02..c4fe7c784cf 100644
--- a/src/corelib/serialization/qdatastream_p.h
+++ b/src/corelib/serialization/qdatastream_p.h
@@ -24,7 +24,6 @@ QT_BEGIN_NAMESPACE
 class QDataStreamPrivate
 {
 public:
-    int transactionDepth = 0;
 };
 #endif