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

["Yu, Jin" <jin.yu@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
> Sent: Wednesday, September 11, 2019 4:44 PM
> To: Yu, Jin <jin.yu@intel.com>; dev@dpdk.org
> Cc: Liu, Changpeng <changpeng.liu@intel.com>; Bie, Tiwei
> <tiwei.bie@intel.com>; Wang, Zhihong <zhihong.wang@intel.com>; Lin Li
> <lilin24@baidu.com>; Xun Ni <nixun@baidu.com>; Yu Zhang
> <zhangyu31@baidu.com>
> Subject: Re: [PATCH v6 05/10] vhost: checkout and cleanup the resubmit inflight
> information
> 
> 
> 
> On 9/11/19 4:50 AM, Yu, Jin wrote:
> >> -----Original Message-----
> >> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
> >> Sent: Monday, September 9, 2019 6:21 PM
> >> To: Yu, Jin <jin.yu@intel.com>; dev@dpdk.org
> >> Cc: Liu, Changpeng <changpeng.liu@intel.com>; Bie, Tiwei
> >> <tiwei.bie@intel.com>; Wang, Zhihong <zhihong.wang@intel.com>; Lin Li
> >> <lilin24@baidu.com>; Xun Ni <nixun@baidu.com>; Yu Zhang
> >> <zhangyu31@baidu.com>
> >> Subject: Re: [PATCH v6 05/10] vhost: checkout and cleanup the
> >> resubmit inflight information
> >>
> >>
> >>
> >> 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.
> > Sorry I don't understand, you means I should check the vq pointer?
> 
> No, I meant vq->inflight_packed should be checked earlier, before if (!vq-
> >inflight_packed->version) {

Yeah you are right, Thanks. Will fix it in next version.
> 
> >>> +
> >>> +	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;
> >>> +}
> >