Re: [dpdk-dev] [PATCH] virtio: Fix enqueue/dequeue can't handle chained vring descriptors.

[Thomas Monjalon <thomas.monjalon@6wind.com>]

Hi Changchun,

Why the title begins with virtio for a patch on vhost?
Could you rephrase it in a positive form?

2015-05-04 14:26, Ouyang Changchun:
> Vring enqueue need consider the 2 cases:
>  1. Vring descriptors chained together, the first one is for virtio header, the rest are for real data;
>  2. Only one descriptor, virtio header and real data share one single descriptor;

Please explain what was not working before.

> So does vring dequeue.
> 
> Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
> ---
>  lib/librte_vhost/vhost_rxtx.c | 60 +++++++++++++++++++++++++++++++------------
>  1 file changed, 44 insertions(+), 16 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
> index 510ffe8..3135883 100644
> --- a/lib/librte_vhost/vhost_rxtx.c
> +++ b/lib/librte_vhost/vhost_rxtx.c
> @@ -59,7 +59,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
>  	struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
>  	uint64_t buff_addr = 0;
>  	uint64_t buff_hdr_addr = 0;
> -	uint32_t head[MAX_PKT_BURST], packet_len = 0;
> +	uint32_t head[MAX_PKT_BURST];
>  	uint32_t head_idx, packet_success = 0;
>  	uint16_t avail_idx, res_cur_idx;
>  	uint16_t res_base_idx, res_end_idx;
> @@ -113,6 +113,10 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
>  	rte_prefetch0(&vq->desc[head[packet_success]]);
>  
>  	while (res_cur_idx != res_end_idx) {
> +		uint32_t offset = 0;
> +		uint32_t data_len, len_to_cpy;
> +		uint8_t plus_hdr = 0;

plus_hdr is not very meaningful to me

I'm not a vhost expert so I won't review the rest.
If nobody comments it in the coming days, it will be accepted.