From: Alejandro Lucero <alejandro.lucero@netronome.com>
To: dev@dpdk.org
Cc: stable@dpdk.org
Subject: [dpdk-dev] [PATCH] net/nfp: fix barrier location
Date: Thu, 22 Feb 2018 11:30:39 +0000 [thread overview]
Message-ID: <1519299039-2475-1-git-send-email-alejandro.lucero@netronome.com> (raw)
The barrier needs to be after reading the DD bit. It has not been
a problem because the potential reads which can not happen before
reading the DD bit seem to be far enough, so the compiler is not
rescheduling them. However, a refactoring could make this problem
to arise.
Fixes: b812daadad0d ("nfp: add Rx and Tx")
Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
---
drivers/net/nfp/nfp_net.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/nfp/nfp_net.c b/drivers/net/nfp/nfp_net.c
index 5180a31..fc501d6 100644
--- a/drivers/net/nfp/nfp_net.c
+++ b/drivers/net/nfp/nfp_net.c
@@ -2019,16 +2019,16 @@ enum nfp_qcp_ptr {
break;
}
+ rxds = &rxq->rxds[rxq->rd_p];
+ if ((rxds->rxd.meta_len_dd & PCIE_DESC_RX_DD) == 0)
+ break;
+
/*
* Memory barrier to ensure that we won't do other
* reads before the DD bit.
*/
rte_rmb();
- rxds = &rxq->rxds[rxq->rd_p];
- if ((rxds->rxd.meta_len_dd & PCIE_DESC_RX_DD) == 0)
- break;
-
/*
* We got a packet. Let's alloc a new mbuff for refilling the
* free descriptor ring as soon as possible
--
1.9.1
next reply other threads:[~2018-02-22 11:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 11:30 Alejandro Lucero [this message]
2018-03-07 11:51 ` [dpdk-dev] [dpdk-stable] " Ferruh Yigit
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