[PULL,10/21] vhost: Delete useless read memory barrier

Commit Message

Jason Wang Sept. 2, 2022, 6:41 a.m. UTC

From: Eugenio Pérez <[e-mail]>

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 <[e-mail]>
Acked-by: Jason Wang <[e-mail]>
Signed-off-by: Jason Wang <[e-mail]>
---
 hw/virtio/vhost-shadow-virtqueue.c | 3 ---
 1 file changed, 3 deletions(-)

Patch

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index b35aeef..8df5296 100644
--- 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);
 }