[PATCH v3 2/7] vhost-user: tighten "reply_supported" scope in "set_vring_addr"

[Laszlo Ersek <lersek@redhat.com>]

In the vhost_user_set_vring_addr() function, we calculate
"reply_supported" unconditionally, even though we'll only need it if
"wait_for_reply" is also true.

Restrict the scope of "reply_supported" to the minimum.

This is purely refactoring -- 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>
---

Notes:
    v3:
    
    - pick up R-b from Phil and Eugenio, T-b from Albert
    
    v2:
    
    - pick up Stefano's R-b

 hw/virtio/vhost-user.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index b4b677c1ce66..64eac317bfb2 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1331,17 +1331,18 @@ static int vhost_user_set_vring_addr(struct vhost_dev *dev,
         .hdr.size = sizeof(msg.payload.addr),
     };
 
-    bool reply_supported = virtio_has_feature(dev->protocol_features,
-                                              VHOST_USER_PROTOCOL_F_REPLY_ACK);
-
     /*
      * wait for a reply if logging is enabled to make sure
      * backend is actually logging changes
      */
     bool wait_for_reply = addr->flags & (1 << VHOST_VRING_F_LOG);
 
-    if (reply_supported && wait_for_reply) {
-        msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
+    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);