bus/vmbus: add missing barrier

The check for event ring being empty needs a barrier
to avoid any over aggressive optimization.
This is same barrier as Linux kernel.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/drivers/bus/vmbus/vmbus_channel.c b/drivers/bus/vmbus/vmbus_channel.c
index 46b3ba3..ff2985c 100644 (file)
--- a/drivers/bus/vmbus/vmbus_channel.c
+++ b/drivers/bus/vmbus/vmbus_channel.c
@@ -199,6 +199,7 @@ bool rte_vmbus_chan_rx_empty(const struct vmbus_channel *channel)
 {
        const struct vmbus_br *br = &channel->rxbr;
 
+       rte_smp_rmb();
        return br->vbr->rindex == br->vbr->windex;
 }