Re: [dpdk-dev] [PATCH 11/17] vhost: add helpers for packed virtqueues

[Tiwei Bie <tiwei.bie@intel.com>]

On Fri, Mar 16, 2018 at 04:21:14PM +0100, Jens Freimann wrote:
> Add some helper functions to set/check descriptor flags
> and toggle the used wrap counter.
> 
> Signed-off-by: Jens Freimann <jfreimann@redhat.com>
[...]
>  
> +static inline void
> +toggle_wrap_counter(struct vhost_virtqueue *vq)
> +{
> +	vq->used_wrap_counter ^= 1;
> +}
> +
> +static inline int
> +desc_is_avail(struct vhost_virtqueue *vq, struct vring_desc_packed *desc)
> +{
> +	if (unlikely(!vq))
> +		return -1;

Maybe it's better to let the caller make sure the vq
won't be NULL.

> +
> +	if (vq->used_wrap_counter == 1)
> +		if ((desc->flags & DESC_AVAIL) && !(desc->flags & DESC_USED))
> +			return 1;
> +	if (vq->used_wrap_counter == 0)

Maybe it's better to use '} else {' here.

Thanks

> +		if (!(desc->flags & DESC_AVAIL) && (desc->flags & DESC_USED))
> +			return 1;
> +	return 0;
> +}