vhost-user: hoist "write_sync", "get_features", "get_u64"

In order to avoid a forward-declaration for "vhost_user_write_sync" in a
subsequent patch, hoist "vhost_user_write_sync" ->
"vhost_user_get_features" -> "vhost_user_get_u64" just above
"vhost_set_vring".

This is purely code movement -- no observable change.

Cc: "Michael S. Tsirkin" <mst@redhat.com> (supporter:vhost)
Cc: Eugenio Perez Martin <eperezma@redhat.com>
Cc: German Maglione <gmaglione@redhat.com>
Cc: Liu Jiang <gerry@linux.alibaba.com>
Cc: Sergio Lopez Pascual <slp@redhat.com>
Cc: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Tested-by: Albert Esteve <aesteve@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20231002203221.17241-6-lersek@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/vhost-user.c

@@ -1073,6 +1073,91 @@ static int vhost_user_set_vring_endian(struct vhost_dev *dev,
     return vhost_user_write(dev, &msg, NULL, 0);
 }
 
+static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64)
+{
+    int ret;
+    VhostUserMsg msg = {
+        .hdr.request = request,
+        .hdr.flags = VHOST_USER_VERSION,
+    };
+
+    if (vhost_user_per_device_request(request) && dev->vq_index != 0) {
+        return 0;
+    }
+
+    ret = vhost_user_write(dev, &msg, NULL, 0);
+    if (ret < 0) {
+        return ret;
+    }
+
+    ret = vhost_user_read(dev, &msg);
+    if (ret < 0) {
+        return ret;
+    }
+
+    if (msg.hdr.request != request) {
+        error_report("Received unexpected msg type. Expected %d received %d",
+                     request, msg.hdr.request);
+        return -EPROTO;
+    }
+
+    if (msg.hdr.size != sizeof(msg.payload.u64)) {
+        error_report("Received bad msg size.");
+        return -EPROTO;
+    }
+
+    *u64 = msg.payload.u64;
+
+    return 0;
+}
+
+static int vhost_user_get_features(struct vhost_dev *dev, uint64_t *features)
+{
+    if (vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features) < 0) {
+        return -EPROTO;
+    }
+
+    return 0;
+}
+
+/* Note: "msg->hdr.flags" may be modified. */
+static int vhost_user_write_sync(struct vhost_dev *dev, VhostUserMsg *msg,
+                                 bool wait_for_reply)
+{
+    int ret;
+
+    if (wait_for_reply) {
+        bool reply_supported = virtio_has_feature(dev->protocol_features,
+                                          VHOST_USER_PROTOCOL_F_REPLY_ACK);
+        if (reply_supported) {
+            msg->hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
+        }
+    }
+
+    ret = vhost_user_write(dev, msg, NULL, 0);
+    if (ret < 0) {
+        return ret;
+    }
+
+    if (wait_for_reply) {
+        uint64_t dummy;
+
+        if (msg->hdr.flags & VHOST_USER_NEED_REPLY_MASK) {
+            return process_message_reply(dev, msg);
+        }
+
+       /*
+        * We need to wait for a reply but the backend does not
+        * support replies for the command we just sent.
+        * Send VHOST_USER_GET_FEATURES which makes all backends
+        * send a reply.
+        */
+        return vhost_user_get_features(dev, &dummy);
+    }
+
+    return 0;
+}
+
 static int vhost_set_vring(struct vhost_dev *dev,
                            unsigned long int request,
                            struct vhost_vring_state *ring)
@@ -1245,91 +1330,6 @@ static int vhost_user_set_vring_err(struct vhost_dev *dev,
     return vhost_set_vring_file(dev, VHOST_USER_SET_VRING_ERR, file);
 }
 
-static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64)
-{
-    int ret;
-    VhostUserMsg msg = {
-        .hdr.request = request,
-        .hdr.flags = VHOST_USER_VERSION,
-    };
-
-    if (vhost_user_per_device_request(request) && dev->vq_index != 0) {
-        return 0;
-    }
-
-    ret = vhost_user_write(dev, &msg, NULL, 0);
-    if (ret < 0) {
-        return ret;
-    }
-
-    ret = vhost_user_read(dev, &msg);
-    if (ret < 0) {
-        return ret;
-    }
-
-    if (msg.hdr.request != request) {
-        error_report("Received unexpected msg type. Expected %d received %d",
-                     request, msg.hdr.request);
-        return -EPROTO;
-    }
-
-    if (msg.hdr.size != sizeof(msg.payload.u64)) {
-        error_report("Received bad msg size.");
-        return -EPROTO;
-    }
-
-    *u64 = msg.payload.u64;
-
-    return 0;
-}
-
-static int vhost_user_get_features(struct vhost_dev *dev, uint64_t *features)
-{
-    if (vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features) < 0) {
-        return -EPROTO;
-    }
-
-    return 0;
-}
-
-/* Note: "msg->hdr.flags" may be modified. */
-static int vhost_user_write_sync(struct vhost_dev *dev, VhostUserMsg *msg,
-                                 bool wait_for_reply)
-{
-    int ret;
-
-    if (wait_for_reply) {
-        bool reply_supported = virtio_has_feature(dev->protocol_features,
-                                          VHOST_USER_PROTOCOL_F_REPLY_ACK);
-        if (reply_supported) {
-            msg->hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
-        }
-    }
-
-    ret = vhost_user_write(dev, msg, NULL, 0);
-    if (ret < 0) {
-        return ret;
-    }
-
-    if (wait_for_reply) {
-        uint64_t dummy;
-
-        if (msg->hdr.flags & VHOST_USER_NEED_REPLY_MASK) {
-            return process_message_reply(dev, msg);
-        }
-
-       /*
-        * We need to wait for a reply but the backend does not
-        * support replies for the command we just sent.
-        * Send VHOST_USER_GET_FEATURES which makes all backends
-        * send a reply.
-        */
-        return vhost_user_get_features(dev, &dummy);
-    }
-
-    return 0;
-}
-
 static int vhost_user_set_vring_addr(struct vhost_dev *dev,
                                      struct vhost_vring_addr *addr)
 {