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

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

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) {

>>> +
>>> +	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;
>>> +}
>