Re: [PATCH] vhost: simplify vhost_dev_init() fail_busyloop label

[Stefano Garzarella]

On Mon, Feb 22, 2021 at 11:49:31AM +0000, Stefan Hajnoczi wrote:
> Requiring a conditional for every goto is tedious:
>
>  if (busyloop_timeout) {
>      goto fail_busyloop;
>  } else {
>      goto fail;
>  }
>
> Move the conditional to into the fail_busyloop label so that it's safe
> to jump to this label unconditionally.
>
> This change makes the migrate_add_blocker() error case more consistent.
> It jumped to fail_busyloop unconditionally whereas the memslots limits
> error case was conditional.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> hw/virtio/vhost.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 6e17d631f7..2a01662b08 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -1388,18 +1388,16 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
>         error_report("vhost backend memory slots limit is less"
>                 " than current number of present memory slots");
>         r = -1;
> -        if (busyloop_timeout) {
> -            goto fail_busyloop;
> -        } else {
> -            goto fail;
> -        }
> +        goto fail_busyloop;
>     }
>
>     return 0;
>
> fail_busyloop:
> -    while (--i >= 0) {
> -        vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, 0);
> +    if (busyloop_timeout) {
> +        while (--i >= 0) {
> +            vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, 0);
> +        }
>     }
> fail:
>     hdev->nvqs = n_initialized_vqs;
> --
> 2.29.2