[RFC PATCH for 8.0 07/13] virtio: refactor qemu_put_virtqueue_element

["Eugenio Pérez" <eperezma@redhat.com>]

The core of the function is useful to transform from VirtQueueElement
to VirtQueueElementOld. Extract these from qemu_put_virtqueue_element,
and leave there the handling of QEMUFile.

No functional change intended.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/virtio.c | 45 ++++++++++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index b0245ce4e8..bc3b474065 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2360,36 +2360,43 @@ void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz)
     return elem;
 }
 
-void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f,
-                                VirtQueueElement *elem)
+/* Convert VirtQueueElement to VirtQueueElementOld */
+static void qemu_put_virtqueue_element_old(const VirtQueueElement *elem,
+                                           VirtQueueElementOld *data)
 {
-    VirtQueueElementOld data;
-    int i;
+    memset(data, 0, sizeof(*data));
+    data->index = elem->index;
+    data->in_num = elem->in_num;
+    data->out_num = elem->out_num;
 
-    memset(&data, 0, sizeof(data));
-    data.index = elem->index;
-    data.in_num = elem->in_num;
-    data.out_num = elem->out_num;
-
-    for (i = 0; i < elem->in_num; i++) {
-        data.in_addr[i] = elem->in_addr[i];
+    for (int i = 0; i < elem->in_num; i++) {
+        data->in_addr[i] = elem->in_addr[i];
     }
 
-    for (i = 0; i < elem->out_num; i++) {
-        data.out_addr[i] = elem->out_addr[i];
+    for (int i = 0; i < elem->out_num; i++) {
+        data->out_addr[i] = elem->out_addr[i];
     }
 
-    for (i = 0; i < elem->in_num; i++) {
-        /* Base is overwritten by virtqueue_map when loading.  Do not
-         * save it, as it would leak the QEMU address space layout.  */
-        data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
+    for (int i = 0; i < elem->in_num; i++) {
+        /*
+         * Base is overwritten by virtqueue_map when loading.  Do not
+         * save it, as it would leak the QEMU address space layout.
+         */
+        data->in_sg[i].iov_len = elem->in_sg[i].iov_len;
     }
 
-    for (i = 0; i < elem->out_num; i++) {
+    for (int i = 0; i < elem->out_num; i++) {
         /* Do not save iov_base as above.  */
-        data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
+        data->out_sg[i].iov_len = elem->out_sg[i].iov_len;
     }
+}
+
+void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f,
+                                VirtQueueElement *elem)
+{
+    VirtQueueElementOld data;
 
+    qemu_put_virtqueue_element_old(elem, &data);
     if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
         qemu_put_be32s(f, &elem->ndescs);
     }
-- 
2.31.1