vhost: Delete useless read memory barrier

As discussed in previous series [1], this memory barrier is useless with
the atomic read of used idx at vhost_svq_more_used. Deleting it.

[1] https://lists.nongnu.org/archive/html/qemu-devel/2022-07/msg02616.html

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index b35aeef4bd95dcbcec25d489afd6be8299b13658..8df5296f247689d8b7c60c4acac3c70b693d34cd 100644 (file)
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -509,9 +509,6 @@ size_t vhost_svq_poll(VhostShadowVirtqueue *svq)
         if (unlikely(g_get_monotonic_time() - start_us > 10e6)) {
             return 0;
         }
-
-        /* Make sure we read new used_idx */
-        smp_rmb();
     } while (true);
 }