Re: [dpdk-dev] [PATCH v7 05/13] vhost: add packed ring single dequeue

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 10/21/19 5:40 PM, Marvin Liu wrote:
> Add vhost single packet dequeue function for packed ring and meanwhile
> left space for shadow used ring update function.
> 
> Signed-off-by: Marvin Liu <yong.liu@intel.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> 
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 4ddf26567..317be1aed 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -1635,6 +1635,61 @@ virtio_dev_tx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
>  	return i;
>  }
>  
> +static __rte_always_inline int
> +vhost_dequeue_single_packed(struct virtio_net *dev,
> +			    struct vhost_virtqueue *vq,
> +			    struct rte_mempool *mbuf_pool,
> +			    struct rte_mbuf **pkts,
> +			    uint16_t *buf_id,
> +			    uint16_t *desc_count)
> +{
> +	struct buf_vector buf_vec[BUF_VECTOR_MAX];
> +	uint32_t dummy_len;
> +	uint16_t nr_vec = 0;
> +	int err;
> +
> +	if (unlikely(fill_vec_buf_packed(dev, vq,
> +					 vq->last_avail_idx, desc_count,
> +					 buf_vec, &nr_vec,
> +					 buf_id, &dummy_len,
> +					 VHOST_ACCESS_RO) < 0))
> +		return -1;
> +
> +	*pkts = rte_pktmbuf_alloc(mbuf_pool);

This is not properly rebased, you should no more call this API directly,
but instead virtio_dev_pktmbuf_alloc() which was introduced withg
flavio's patch.

> +	if (unlikely(*pkts == NULL)) {
> +		RTE_LOG(ERR, VHOST_DATA,
> +			"Failed to allocate memory for mbuf.\n");
> +		return -1;
> +	}
> +
> +	err = copy_desc_to_mbuf(dev, vq, buf_vec, nr_vec, *pkts,
> +				mbuf_pool);
> +	if (unlikely(err)) {
> +		rte_pktmbuf_free(*pkts);
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +static __rte_unused int
> +virtio_dev_tx_single_packed(struct virtio_net *dev,
> +			    struct vhost_virtqueue *vq,
> +			    struct rte_mempool *mbuf_pool,
> +			    struct rte_mbuf **pkts)
> +{
> +
> +	uint16_t buf_id, desc_count;
> +
> +	if (vhost_dequeue_single_packed(dev, vq, mbuf_pool, pkts, &buf_id,
> +					&desc_count))
> +		return -1;
> +
> +	vq_inc_last_avail_packed(vq, desc_count);
> +
> +	return 0;
> +}
> +
>  static __rte_noinline uint16_t
>  virtio_dev_tx_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
>  	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
>