Re: [PATCH v2 2/7] vhost-user: tighten "reply_supported" scope in "set_vring_addr"

[Laszlo Ersek <lersek@redhat.com>]

On 8/30/23 15:40, Laszlo Ersek wrote:
> 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>
> ---
> 
> Notes:
>     v2:
>     
>     - pick up Stefano's R-b
> 
>  hw/virtio/vhost-user.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)

identical to v1, so:

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

from
<http://mid.mail-archive.com/6c12069e-da31-9758-4972-7121ab5ffdee@linaro.org>.

Laszlo

> 
> 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);
>