[dpdk-dev] [PATCH v2 2/3] net/vhost: fix queue update

[Maxime Coquelin]

Now that the vhost library saves the guest notifications
enablement value in its virtqueues metadata, it is not
necessary to do it in the vring_state_changed callback.

One effect of the patch is also to prevent possible
deadlock happening in vhost library.

Fixes: 604052ae5395 ("net/vhost: support queue update")

Reported-by: Yinan Wang <yinan.w...@intel.com>
Tested-by: Yinan Wang <yinan.w...@intel.com>
Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
 drivers/net/vhost/rte_eth_vhost.c | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/drivers/net/vhost/rte_eth_vhost.c 
b/drivers/net/vhost/rte_eth_vhost.c
index bbf79b2c0e..951929c663 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -94,7 +94,6 @@ struct vhost_queue {
        struct rte_mempool *mb_pool;
        uint16_t port;
        uint16_t virtqueue_id;
-       bool intr_en;
        struct vhost_stats stats;
 };
 
@@ -547,8 +546,6 @@ eth_rxq_intr_enable(struct rte_eth_dev *dev, uint16_t qid)
        rte_vhost_enable_guest_notification(vq->vid, (qid << 1) + 1, 1);
        rte_wmb();
 
-       vq->intr_en = true;
-
        return ret;
 }
 
@@ -574,8 +571,6 @@ eth_rxq_intr_disable(struct rte_eth_dev *dev, uint16_t qid)
        rte_vhost_enable_guest_notification(vq->vid, (qid << 1) + 1, 0);
        rte_wmb();
 
-       vq->intr_en = false;
-
        return 0;
 }
 
@@ -841,7 +836,6 @@ vring_conf_update(int vid, struct rte_eth_dev *eth_dev, 
uint16_t vring_id)
        struct rte_eth_conf *dev_conf = &eth_dev->data->dev_conf;
        struct pmd_internal *internal = eth_dev->data->dev_private;
        struct rte_vhost_vring vring;
-       struct vhost_queue *vq;
        int rx_idx = vring_id % 2 ? (vring_id - 1) >> 1 : -1;
        int ret = 0;
 
@@ -853,21 +847,17 @@ vring_conf_update(int vid, struct rte_eth_dev *eth_dev, 
uint16_t vring_id)
            rte_atomic32_read(&internal->dev_attached) &&
            rte_atomic32_read(&internal->started) &&
            dev_conf->intr_conf.rxq) {
-               vq = eth_dev->data->rx_queues[rx_idx];
                ret = rte_vhost_get_vhost_vring(vid, vring_id, &vring);
-               if (!ret) {
-                       if (vring.kickfd !=
-                           eth_dev->intr_handle->efds[rx_idx]) {
-                               VHOST_LOG(INFO,
-                                         "kickfd for rxq-%d was changed.\n",
-                                         rx_idx);
-                               eth_dev->intr_handle->efds[rx_idx] =
-                                                                  vring.kickfd;
-                       }
+               if (ret) {
+                       VHOST_LOG(ERR, "Failed to get vring %d information.\n",
+                                       vring_id);
+                       return ret;
+               }
 
-                       rte_vhost_enable_guest_notification(vid, vring_id,
-                                                           vq->intr_en);
-                       rte_wmb();
+               if (vring.kickfd != eth_dev->intr_handle->efds[rx_idx]) {
+                       VHOST_LOG(INFO, "kickfd for rxq-%d was changed.\n",
+                                         rx_idx);
+                       eth_dev->intr_handle->efds[rx_idx] = vring.kickfd;
                }
        }
 
-- 
2.26.2