[dpdk-stable] patch 'net/ixgbe: fix received packets number for ARM' has been queued to stable release 16.11.1

[Yuanhan Liu]

Hi,

FYI, your patch has been queued to stable release 16.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable
yet. It will be pushed if I get no objections before 02/18/17.
So please shout if anyone has objections.

Thanks.

	--yliu

---
>From 2e162cbaa88615ec67763a9558cf72e65fd54414 Mon Sep 17 00:00:00 2001
From: Jianbo Liu <jianbo.liu at linaro.org>
Date: Thu, 9 Feb 2017 12:05:25 +0800
Subject: [PATCH] net/ixgbe: fix received packets number for ARM

[ upstream commit a98212de4ac958f5919a96771287a9617a4e5848 ]

To get better performance, Rx bulk alloc recv function will scan 8 descs
in one time, but the statuses are not consistent on ARM platform because
the memory allocated for Rx descriptors is cacheable hugepages.
This patch is to calculate the number of received packets by scan DD bit
sequentially, and stops when meeting the first packet with DD bit unset.

Fixes: 7431041062b9 ("ixgbe: allow rx bulk alloc")

Signed-off-by: Jianbo Liu <jianbo.liu at linaro.org>
Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
---
 drivers/net/ixgbe/ixgbe_rxtx.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c b/drivers/net/ixgbe/ixgbe_rxtx.c
index b2d9f45..c61ce47 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -1402,17 +1402,19 @@ ixgbe_rx_scan_hw_ring(struct ixgbe_rx_queue *rxq)
 	for (i = 0; i < RTE_PMD_IXGBE_RX_MAX_BURST;
 	     i += LOOK_AHEAD, rxdp += LOOK_AHEAD, rxep += LOOK_AHEAD) {
 		/* Read desc statuses backwards to avoid race condition */
-		for (j = LOOK_AHEAD-1; j >= 0; --j)
+		for (j = 0; j < LOOK_AHEAD; j++)
 			s[j] = rte_le_to_cpu_32(rxdp[j].wb.upper.status_error);
 
-		for (j = LOOK_AHEAD - 1; j >= 0; --j)
-			pkt_info[j] = rte_le_to_cpu_32(rxdp[j].wb.lower.
-						       lo_dword.data);
+		rte_smp_rmb();
 
 		/* Compute how many status bits were set */
-		nb_dd = 0;
-		for (j = 0; j < LOOK_AHEAD; ++j)
-			nb_dd += s[j] & IXGBE_RXDADV_STAT_DD;
+		for (nb_dd = 0; nb_dd < LOOK_AHEAD &&
+				(s[nb_dd] & IXGBE_RXDADV_STAT_DD); nb_dd++)
+			;
+
+		for (j = 0; j < nb_dd; j++)
+			pkt_info[j] = rte_le_to_cpu_32(rxdp[j].wb.lower.
+						       lo_dword.data);
 
 		nb_rx += nb_dd;
 
-- 
1.9.0