[dpdk-stable] patch 'net/i40e: fix rearm check in AVX2 Rx' has been queued to stable release 18.05.1

[Christian Ehrhardt]

Hi,

FYI, your patch has been queued to stable release 18.05.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 08/16/18. So please
shout if anyone has objections.

Thanks.

Christian Ehrhardt <christian.ehrhardt at canonical.com>

---
>From 430b9e8217ad4ea38450d6b31e0768e9c4ad5ed3 Mon Sep 17 00:00:00 2001
From: Harry van Haaren <harry.van.haaren at intel.com>
Date: Mon, 30 Jul 2018 18:34:19 +0100
Subject: [PATCH] net/i40e: fix rearm check in AVX2 Rx

[ upstream commit f5dd9a88dedd54fa89a25c9a10d39f3abe31e5c2 ]

This commit fixes an infinite loop bug that could occur
if the i40e AVX2 driver is used, and high traffic rates
cause the mempool from which the rxq pulls mbufs to become
empty.

The result would be an infinite loop of checking if we
should perform an rx rearm, calling the function and an
error return due the the mempool being emtpy.

The fix is to align the code in the AVX2 driver with the
SSE driver, where an if() is used instead of a while(),
allowing the thread to return from i40e rx function even
if the mempool is empty.

Fixes: dafadd73762e ("net/i40e: add AVX2 Rx function")

Reported-by: David Coyle <david.coyle at intel.com>
Signed-off-by: Harry van Haaren <harry.van.haaren at intel.com>
Acked-by: Brendan Ryan <brendan.ryan at intel.com>
Tested-by: David Coyle <david.coyle at intel.com>
---
 drivers/net/i40e/i40e_rxtx_vec_avx2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/i40e/i40e_rxtx_vec_avx2.c b/drivers/net/i40e/i40e_rxtx_vec_avx2.c
index dbcb61f38..23179b3b8 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_avx2.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_avx2.c
@@ -188,7 +188,7 @@ _recv_raw_pkts_vec_avx2(struct i40e_rx_queue *rxq, struct rte_mbuf **rx_pkts,
 	/* See if we need to rearm the RX queue - gives the prefetch a bit
 	 * of time to act
 	 */
-	while (rxq->rxrearm_nb > RTE_I40E_RXQ_REARM_THRESH)
+	if (rxq->rxrearm_nb > RTE_I40E_RXQ_REARM_THRESH)
 		i40e_rxq_rearm(rxq);
 
 	/* Before we start moving massive data around, check to see if
-- 
2.17.1