[RFC PATCH v2 4/9] vhost: fix async access

[David Marchand]

vq->async accesses must be protected with vq->access_lock.

Fixes: eb666d24085f ("vhost: fix async unregister deadlock")
Fixes: 0c0935c5f794 ("vhost: allow to check in-flight packets for async vhost")
Cc: sta...@dpdk.org

Signed-off-by: David Marchand <david.march...@redhat.com>
---
 lib/vhost/vhost.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 2f96a28dac..a93e41f314 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1753,27 +1753,23 @@ rte_vhost_async_channel_unregister(int vid, uint16_t 
queue_id)
        if (vq == NULL)
                return ret;
 
-       ret = 0;
-
-       if (!vq->async)
-               return ret;
-
        if (!rte_spinlock_trylock(&vq->access_lock)) {
                VHOST_LOG_CONFIG(ERR, "(%s) failed to unregister async channel, 
virtqueue busy.\n",
                                dev->ifname);
-               return -1;
+               return ret;
        }
 
-       if (vq->async->pkts_inflight_n) {
+       if (!vq->async) {
+               ret = 0;
+       } else if (vq->async->pkts_inflight_n) {
                VHOST_LOG_CONFIG(ERR, "(%s) failed to unregister async 
channel.\n", dev->ifname);
                VHOST_LOG_CONFIG(ERR, "(%s) inflight packets must be completed 
before unregistration.\n",
                        dev->ifname);
-               ret = -1;
-               goto out;
+       } else {
+               vhost_free_async_mem(vq);
+               ret = 0;
        }
 
-       vhost_free_async_mem(vq);
-out:
        rte_spinlock_unlock(&vq->access_lock);
 
        return ret;
@@ -1891,9 +1887,6 @@ rte_vhost_async_get_inflight(int vid, uint16_t queue_id)
        if (vq == NULL)
                return ret;
 
-       if (!vq->async)
-               return ret;
-
        if (!rte_spinlock_trylock(&vq->access_lock)) {
                VHOST_LOG_CONFIG(DEBUG,
                        "(%s) failed to check in-flight packets. virtqueue 
busy.\n",
@@ -1901,7 +1894,9 @@ rte_vhost_async_get_inflight(int vid, uint16_t queue_id)
                return ret;
        }
 
-       ret = vq->async->pkts_inflight_n;
+       if (vq->async)
+               ret = vq->async->pkts_inflight_n;
+
        rte_spinlock_unlock(&vq->access_lock);
 
        return ret;
-- 
2.23.0