Re: [dpdk-dev] [PATCH v3] net/vhost: fix vhost invalid state

["Chen, Junjie J" <junjie.j.chen@intel.com>]

> 
> 
> 
> On 04/12/2018 09:21 AM, Tan, Jianfeng wrote:
> >
> >
> > On 4/12/2018 1:02 AM, Junjie Chen wrote:
> >> dev_start sets *dev_attached* after setup queues, this sets device to
> >> invalid state since no frontend is attached. Also destroy_device set
> >> *started* to zero which makes *allow_queuing* always zero until
> >> dev_start get called again. Actually, we should not determine queues
> >> existence by
> >> *dev_attached* but by queues pointers or other separated variable(s).
> >>
> >> Fixes: 30a701a53737 ("net/vhost: fix crash when creating vdev
> >> dynamically")
> >>
> >> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
> >> Tested-by: Jens Freimann <jfreimann@redhat.com>
> >
> > Overall, looks great to me except a nit below.
> >
> > Reviewed-by: Jianfeng Tan <jianfeng.tan@intel.com>
> 
> Thanks Jianfeng, I can handle the small change while applying.
> 
> Can you confirm that it is implied that the queue are already allocated, else we
> wouldn't find the internal resource and quit earlier (in case of eth_dev_close
> called twice for example)?

That is required, otherwise it generate segfault if we close device before queue setup. For example we
execute following steps in testpmd:
1. port attach
2. ctrl+D

> 
> Thanks,
> Maxime
> 
> >
> >> ---
> >> Changes in v3:
> >> - remove useless log in queue status showing Changes in v2:
> >> - use started to determine vhost queues readiness
> >> - revert setting started to zero in destroy_device
> >>   drivers/net/vhost/rte_eth_vhost.c | 59
> >> +++++++++++++++++++--------------------
> >>   1 file changed, 29 insertions(+), 30 deletions(-)
> >>
> >> diff --git a/drivers/net/vhost/rte_eth_vhost.c
> >> b/drivers/net/vhost/rte_eth_vhost.c
> >> index 11b6076..e392d71 100644
> >> --- a/drivers/net/vhost/rte_eth_vhost.c
> >> +++ b/drivers/net/vhost/rte_eth_vhost.c
> >> @@ -528,10 +528,11 @@ update_queuing_status(struct rte_eth_dev
> *dev)
> >>       unsigned int i;
> >>       int allow_queuing = 1;
> >> -    if (rte_atomic32_read(&internal->dev_attached) == 0)
> >> +    if (!dev->data->rx_queues || !dev->data->tx_queues)
> >>           return;
> >> -    if (rte_atomic32_read(&internal->started) == 0)
> >> +    if (rte_atomic32_read(&internal->started) == 0 ||
> >> +        rte_atomic32_read(&internal->dev_attached) == 0)
> >>           allow_queuing = 0;
> >>       /* Wait until rx/tx_pkt_burst stops accessing vhost device */
> >> @@ -607,13 +608,10 @@ new_device(int vid)
> >>   #endif
> >>       internal->vid = vid;
> >> -    if (eth_dev->data->rx_queues && eth_dev->data->tx_queues) {
> >> +    if (rte_atomic32_read(&internal->started) == 1)
> >>           queue_setup(eth_dev, internal);
> >> -        rte_atomic32_set(&internal->dev_attached, 1);
> >> -    } else {
> >> -        RTE_LOG(INFO, PMD, "RX/TX queues have not setup yet\n");
> >> -        rte_atomic32_set(&internal->dev_attached, 0);
> >> -    }
> >> +    else
> >> +        RTE_LOG(INFO, PMD, "RX/TX queues not exist yet\n");
> >>       for (i = 0; i < rte_vhost_get_vring_num(vid); i++)
> >>           rte_vhost_enable_guest_notification(vid, i, 0); @@ -622,6
> >> +620,7 @@ new_device(int vid)
> >>       eth_dev->data->dev_link.link_status = ETH_LINK_UP;
> >> +    rte_atomic32_set(&internal->dev_attached, 1);
> >>       update_queuing_status(eth_dev);
> >>       RTE_LOG(INFO, PMD, "Vhost device %d created\n", vid); @@
> >> -651,23 +650,24 @@ destroy_device(int vid)
> >>       eth_dev = list->eth_dev;
> >>       internal = eth_dev->data->dev_private;
> >> -    rte_atomic32_set(&internal->started, 0);
> >> -    update_queuing_status(eth_dev);
> >>       rte_atomic32_set(&internal->dev_attached, 0);
> >> +    update_queuing_status(eth_dev);
> >>       eth_dev->data->dev_link.link_status = ETH_LINK_DOWN;
> >> -    for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
> >> -        vq = eth_dev->data->rx_queues[i];
> >> -        if (vq == NULL)
> >> -            continue;
> >> -        vq->vid = -1;
> >> -    }
> >> -    for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
> >> -        vq = eth_dev->data->tx_queues[i];
> >> -        if (vq == NULL)
> >> -            continue;
> >> -        vq->vid = -1;
> >> +    if (eth_dev->data->rx_queues && eth_dev->data->tx_queues) {
> >> +        for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
> >> +            vq = eth_dev->data->rx_queues[i];
> >> +            if (!vq)
> >> +                continue;
> >> +            vq->vid = -1;
> >> +        }
> >> +        for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
> >> +            vq = eth_dev->data->tx_queues[i];
> >> +            if (!vq)
> >> +                continue;
> >> +            vq->vid = -1;
> >> +        }
> >>       }
> >>       state = vring_states[eth_dev->data->port_id];
> >> @@ -792,11 +792,7 @@ eth_dev_start(struct rte_eth_dev *eth_dev)
> >>   {
> >>       struct pmd_internal *internal = eth_dev->data->dev_private;
> >> -    if (unlikely(rte_atomic32_read(&internal->dev_attached) == 0)) {
> >> -        queue_setup(eth_dev, internal);
> >> -        rte_atomic32_set(&internal->dev_attached, 1);
> >> -    }
> >> -
> >> +    queue_setup(eth_dev, internal);
> >>       rte_atomic32_set(&internal->started, 1);
> >>       update_queuing_status(eth_dev); @@ -836,10 +832,13 @@
> >> eth_dev_close(struct rte_eth_dev *dev)
> >>       pthread_mutex_unlock(&internal_list_lock);
> >>       rte_free(list);
> >> -    for (i = 0; i < dev->data->nb_rx_queues; i++)
> >> -        rte_free(dev->data->rx_queues[i]);
> >> -    for (i = 0; i < dev->data->nb_tx_queues; i++)
> >> -        rte_free(dev->data->tx_queues[i]);
> >> +    if (dev->data->rx_queues)
> >
> > This is implied that rx_queues is already allocated. So I don't think
> > we need this.
> >
> >> +        for (i = 0; i < dev->data->nb_rx_queues; i++)
> >> +            rte_free(dev->data->rx_queues[i]);
> >> +
> >> +    if (dev->data->tx_queues)
> >> +        for (i = 0; i < dev->data->nb_tx_queues; i++)
> >> +            rte_free(dev->data->tx_queues[i]);
> >>       rte_free(dev->data->mac_addrs);
> >>       free(internal->dev_name);
> >