Re: [PATCH 1/2] vhost-user: Refactor vhost acked features saving

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Sep 26, 2022 at 02:36:40PM +0800, huangy81@chinatelecom.cn wrote:
> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> 
> Abstract vhost acked features saving into
> vhost_user_save_acked_features, export it as util function.
> 
> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn>
> ---
>  include/net/vhost-user.h |  2 ++
>  net/vhost-user.c         | 35 +++++++++++++++++++----------------
>  2 files changed, 21 insertions(+), 16 deletions(-)
> 
> diff --git a/include/net/vhost-user.h b/include/net/vhost-user.h
> index 5bcd8a6285..00d46613d3 100644
> --- a/include/net/vhost-user.h
> +++ b/include/net/vhost-user.h
> @@ -14,5 +14,7 @@
>  struct vhost_net;
>  struct vhost_net *vhost_user_get_vhost_net(NetClientState *nc);
>  uint64_t vhost_user_get_acked_features(NetClientState *nc);
> +void vhost_user_save_acked_features(NetClientState *nc,
> +                                    bool cleanup);
>  
>  #endif /* VHOST_USER_H */
> diff --git a/net/vhost-user.c b/net/vhost-user.c
> index b1a0247b59..c512cc9727 100644
> --- a/net/vhost-user.c
> +++ b/net/vhost-user.c
> @@ -45,24 +45,31 @@ uint64_t vhost_user_get_acked_features(NetClientState *nc)
>      return s->acked_features;
>  }
>  
> -static void vhost_user_stop(int queues, NetClientState *ncs[])
> +void vhost_user_save_acked_features(NetClientState *nc, bool cleanup)
>  {
>      NetVhostUserState *s;
> +
> +    s = DO_UPCAST(NetVhostUserState, nc, nc);
> +    if (s->vhost_net) {
> +        uint64_t features = vhost_net_get_acked_features(s->vhost_net);
> +        if (features) {
> +            s->acked_features = features;
> +        }

Note it does not set  acked_features if features are 0.
Which might be the case for legacy ...
I will need to analyze this more to figure out what's
the correct behaviour....

Stefano? Raphael?

> +
> +        if (cleanup) {
> +            vhost_net_cleanup(s->vhost_net);
> +        }
> +    }
> +}
> +
> +static void vhost_user_stop(int queues, NetClientState *ncs[])
> +{
>      int i;
>  
>      for (i = 0; i < queues; i++) {
>          assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
>  
> -        s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
> -
> -        if (s->vhost_net) {
> -            /* save acked features */
> -            uint64_t features = vhost_net_get_acked_features(s->vhost_net);
> -            if (features) {
> -                s->acked_features = features;
> -            }
> -            vhost_net_cleanup(s->vhost_net);
> -        }
> +        vhost_user_save_acked_features(ncs[i], true);
>      }
>  }
>  
> @@ -251,11 +258,7 @@ static void chr_closed_bh(void *opaque)
>      s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
>  
>      for (i = queues -1; i >= 0; i--) {
> -        s = DO_UPCAST(NetVhostUserState, nc, ncs[i]);
> -
> -        if (s->vhost_net) {
> -            s->acked_features = vhost_net_get_acked_features(s->vhost_net);
> -        }
> +        vhost_user_save_acked_features(ncs[i], false);
>      }
>  
>      qmp_set_link(name, false, &err);
> -- 
> 2.27.0