Re: [PATCH RFC 2/2] vhost: packed ring support

[Jason Wang]

On 2018å02æ27æ 17:03, Tiwei Bie wrote:
> On Wed, Feb 14, 2018 at 10:37:09AM +0800, Jason Wang wrote:
> [...]
> > +static void set_desc_used(struct vhost_virtqueue *vq,
> > +			  struct vring_desc_packed *desc, bool wrap_counter)
> > +{
> > +	__virtio16 flags = desc->flags;
> > +
> > +	if (wrap_counter) {
> > +		desc->flags |= cpu_to_vhost16(vq, DESC_AVAIL);
> > +		desc->flags |= cpu_to_vhost16(vq, DESC_USED);
> > +	} else {
> > +		desc->flags &= ~cpu_to_vhost16(vq, DESC_AVAIL);
> > +		desc->flags &= ~cpu_to_vhost16(vq, DESC_USED);
> > +	}
> > +
> > +	desc->flags = flags;
> The `desc->flags` is restored after the change.

Right, will fix.

> > +}
> > +
> > +static int vhost_get_vq_desc_packed(struct vhost_virtqueue *vq,
> > +				    struct iovec iov[], unsigned int iov_size,
> > +				    unsigned int *out_num, unsigned int *in_num,
> > +				    struct vhost_log *log,
> > +				    unsigned int *log_num)
> > +{
> > +	struct vring_desc_packed desc;
> > +	int ret, access, i;
> > +	u16 avail_idx = vq->last_avail_idx;
> > +
> > +	/* When we start there are none of either input nor output. */
> > +	*out_num = *in_num = 0;
> > +	if (unlikely(log))
> > +		*log_num = 0;
> > +
> > +	do {
> > +		unsigned int iov_count = *in_num + *out_num;
> > +
> > +		i = vq->last_avail_idx & (vq->num - 1);
> The queue size may not be a power of 2 in packed ring.

Will fix this too.

Thanks

> Best regards,
> Tiwei Bie