From: Stephen Hemminger <stephen@networkplumber.org>
Date: Thu, 30 Apr 2020 19:08:49 +0000 (-0700)
Subject: bus/vmbus: add missing barrier
X-Git-Url: http://git.droids-corp.org/?p=dpdk.git;a=commitdiff_plain;h=1c33435a58f307c1800a79220122026f56fee450

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 46b3ba3f9f..ff2985c257 100644
--- 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;
 }