Re: [dpdk-dev] [PATCH v6 05/10] vhost: checkout and cleanup the resubmit inflight information

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

On 8/29/19 4:12 PM, JinYu wrote:
> This patch shows how to checkout the inflight ring and construct
> the resubmit information also include destroying resubmit info.
> 
> Signed-off-by: Lin Li <lilin24@baidu.com>
> Signed-off-by: Xun Ni <nixun@baidu.com>
> Signed-off-by: Yu Zhang <zhangyu31@baidu.com>
> Signed-off-by: Jin Yu <jin.yu@intel.com>
> ---
>  lib/librte_vhost/rte_vhost.h  |  19 ++++
>  lib/librte_vhost/vhost.c      |  29 ++++-
>  lib/librte_vhost/vhost.h      |   9 ++
>  lib/librte_vhost/vhost_user.c | 197 ++++++++++++++++++++++++++++++++++
>  4 files changed, 253 insertions(+), 1 deletion(-)
> 
...
> +static int
> +vhost_check_queue_inflights_packed(struct virtio_net *dev,
> +						 struct vhost_virtqueue *vq)
> +{
> +	uint16_t i = 0;
> +	uint16_t resubmit_num = 0, old_used_idx, num;
> +	struct rte_vhost_resubmit_info *resubmit = NULL;
> +	struct inflight_info_packed *inflight_packed;
> +
> +	if (!(dev->protocol_features &
> +		(1ULL << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD)))
> +		return RTE_VHOST_MSG_RESULT_OK;
> +
> +	if (!vq->inflight_packed->version) {
> +		vq->inflight_packed->version = INFLIGHT_VERSION;
> +		return RTE_VHOST_MSG_RESULT_OK;
> +	}
> +
> +	if ((!vq->inflight_packed))
> +		return RTE_VHOST_MSG_RESULT_ERR;

It needs to be checked before before being dereferenced.

> +
> +	inflight_packed = vq->inflight_packed;
> +	vq->resubmit_inflight = NULL;
> +	vq->global_counter = 0;
> +	old_used_idx = inflight_packed->old_used_idx;
> +
> +	if (inflight_packed->used_idx != old_used_idx) {
> +		if (inflight_packed->desc[old_used_idx].inflight == 0) {
> +			inflight_packed->old_used_idx =
> +				inflight_packed->used_idx;
> +			inflight_packed->old_used_wrap_counter =
> +				inflight_packed->used_wrap_counter;
> +			inflight_packed->old_free_head =
> +				inflight_packed->free_head;
> +		} else {
> +			inflight_packed->used_idx =
> +				inflight_packed->old_used_idx;
> +			inflight_packed->used_wrap_counter =
> +				inflight_packed->old_used_wrap_counter;
> +			inflight_packed->free_head =
> +				inflight_packed->old_free_head;
> +		}
> +	}
> +
> +	for (i = 0; i < inflight_packed->desc_num; i++) {
> +		if (inflight_packed->desc[i].inflight == 1)
> +			resubmit_num++;
> +	}
> +
> +	if (resubmit_num) {
> +		resubmit = calloc(1, sizeof(struct rte_vhost_resubmit_info));
> +		if (resubmit == NULL) {
> +			RTE_LOG(ERR, VHOST_CONFIG,
> +			 "Failed to allocate memory for resubmit info.\n");
> +			return RTE_VHOST_MSG_RESULT_ERR;
> +		}
> +
> +		resubmit->resubmit_list = calloc(resubmit_num,
> +			sizeof(struct rte_vhost_resubmit_desc));
> +		if (resubmit->resubmit_list == NULL) {
> +			RTE_LOG(ERR, VHOST_CONFIG,
> +			 "Failed to allocate memory for resubmit desc.\n");
> +			return RTE_VHOST_MSG_RESULT_ERR;
> +		}
> +
> +		num = 0;
> +		for (i = 0; i < inflight_packed->desc_num; i++) {
> +			if (vq->inflight_packed->desc[i].inflight == 1) {
> +				resubmit->resubmit_list[num].index = i;
> +				resubmit->resubmit_list[num].counter =
> +					inflight_packed->desc[i].counter;
> +				num++;
> +			}
> +		}
> +		resubmit->resubmit_num = num;
> +
> +		if (resubmit->resubmit_num > 1)
> +			qsort(resubmit->resubmit_list, resubmit->resubmit_num,
> +				sizeof(struct rte_vhost_resubmit_desc),
> +				resubmit_desc_compare);
> +
> +		vq->global_counter = resubmit->resubmit_list[0].counter + 1;
> +		vq->resubmit_inflight = resubmit;
> +	}
> +
> +	return RTE_VHOST_MSG_RESULT_OK;
> +}