Re: [PATCH v4 2/3] vhost-user-blk: split vhost_user_blk_sync_config()

[Markus Armbruster <armbru@redhat.com>]

Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:

> Split vhost_user_blk_sync_config() out from
> vhost_user_blk_handle_config_change(), to be reused in the following
> commit.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
>  hw/block/vhost-user-blk.c | 26 +++++++++++++++++++-------
>  1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> index 9e6bbc6950..091d2c6acf 100644
> --- a/hw/block/vhost-user-blk.c
> +++ b/hw/block/vhost-user-blk.c
> @@ -88,27 +88,39 @@ static void vhost_user_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
>      s->blkcfg.wce = blkcfg->wce;
>  }
>  
> +static int vhost_user_blk_sync_config(DeviceState *dev, Error **errp)
> +{
> +    int ret;
> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);

Note for later: all this function does with paramter @dev is cast it to
VirtIODevice *.

> +    VHostUserBlk *s = VHOST_USER_BLK(vdev);
> +
> +    ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
> +                               vdev->config_len, errp);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    memcpy(vdev->config, &s->blkcfg, vdev->config_len);
> +    virtio_notify_config(vdev);
> +
> +    return 0;
> +}
> +
>  static int vhost_user_blk_handle_config_change(struct vhost_dev *dev)
>  {
>      int ret;
> -    VirtIODevice *vdev = dev->vdev;
> -    VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
>      Error *local_err = NULL;
>  
>      if (!dev->started) {
>          return 0;
>      }
>  
> -    ret = vhost_dev_get_config(dev, (uint8_t *)&s->blkcfg,
> -                               vdev->config_len, &local_err);
> +    ret = vhost_user_blk_sync_config(DEVICE(dev->vdev), &local_err);

dev->vdev is a VirtIODevice *.  You cast it to DeviceState * for
vhost_user_blk_sync_config(), which casts it right back.

Could you simply pass it as is instead?

>      if (ret < 0) {
>          error_report_err(local_err);
>          return ret;
>      }
>  
> -    memcpy(dev->vdev->config, &s->blkcfg, vdev->config_len);
> -    virtio_notify_config(dev->vdev);
> -
>      return 0;
>  }