Re: [RFC] vhost-vdpa: make notifiers _init()/_uninit() symmetric

[Jason Wang]

On Sat, Feb 12, 2022 at 12:13 AM Laurent Vivier <lvivier@redhat.com> wrote:
>
> vhost_vdpa_host_notifiers_init() initializes queue notifiers
> for queues "dev->vq_index" to queue "dev->vq_index + dev->nvqs",
> whereas vhost_vdpa_host_notifiers_uninit() uninitializes the
> same notifiers for queue "0" to queue "dev->nvqs".
>
> This asymmetry seems buggy, fix that by using dev->vq_index
> as the base for both.
>
> Fixes: d0416d487bd5 ("vhost-vdpa: map virtqueue notification area if 
> possible")
> Cc: jasowang@redhat.com
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>  hw/virtio/vhost-vdpa.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 04ea43704f5d..9be3dc66580c 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -395,15 +395,6 @@ static void vhost_vdpa_host_notifier_uninit(struct 
> vhost_dev *dev,
>      }
>  }
>
> -static void vhost_vdpa_host_notifiers_uninit(struct vhost_dev *dev, int n)
> -{
> -    int i;
> -
> -    for (i = 0; i < n; i++) {
> -        vhost_vdpa_host_notifier_uninit(dev, i);
> -    }
> -}
> -
>  static int vhost_vdpa_host_notifier_init(struct vhost_dev *dev, int 
> queue_index)
>  {
>      size_t page_size = qemu_real_host_page_size;
> @@ -442,6 +433,15 @@ err:
>      return -1;
>  }
>
> +static void vhost_vdpa_host_notifiers_uninit(struct vhost_dev *dev, int n)
> +{
> +    int i;
> +
> +    for (i = dev->vq_index; i < dev->vq_index + n; i++) {
> +        vhost_vdpa_host_notifier_uninit(dev, i);
> +    }
> +}

Patch looks good but I wonder why we need to move this function?

Thanks

> +
>  static void vhost_vdpa_host_notifiers_init(struct vhost_dev *dev)
>  {
>      int i;
> @@ -455,7 +455,7 @@ static void vhost_vdpa_host_notifiers_init(struct 
> vhost_dev *dev)
>      return;
>
>  err:
> -    vhost_vdpa_host_notifiers_uninit(dev, i);
> +    vhost_vdpa_host_notifiers_uninit(dev, i - dev->vq_index);
>      return;
>  }
>
> --
> 2.34.1
>