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

[Tan, Jianfeng]

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.c...@intel.com>
Tested-by: Jens Freimann <jfreim...@redhat.com>

Overall, looks great to me except a nit below.

Reviewed-by: Jianfeng Tan <jianfeng....@intel.com>

---
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);