patch 'net/hns3: fix next-to-use overflow in SVE Tx' has been queued to stable release 20.11.7

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 20.11.7

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/05/22. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable/commit/cf08ee6b1f4a9d442b078e84e72d06f672b7833a

Thanks.

Luca Boccassi

---
>From cf08ee6b1f4a9d442b078e84e72d06f672b7833a Mon Sep 17 00:00:00 2001
From: Chengwen Feng <fengchengwen at huawei.com>
Date: Mon, 5 Sep 2022 16:59:33 +0800
Subject: [PATCH] net/hns3: fix next-to-use overflow in SVE Tx

[ upstream commit 3efbc3c4027c87c14727a6a5ce13b099cd8d5866 ]

If txq's next-to-use plus nb_pkts equal txq's nb_tx_desc when using
SVE xmit algorithm, the txq's next-to-use will equal nb_tx_desc after
the xmit, this does not cause Tx exceptions, but may affect other ops
that depend on this field, such as tx_descriptor_status.

Fixes: f0c243a6cb6f ("net/hns3: support SVE Tx")

Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
Signed-off-by: Dongdong Liu <liudongdong3 at huawei.com>
---
 drivers/net/hns3/hns3_rxtx_vec_sve.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/hns3/hns3_rxtx_vec_sve.c b/drivers/net/hns3/hns3_rxtx_vec_sve.c
index 67bf8ccdc5..e7446eb017 100644
--- a/drivers/net/hns3/hns3_rxtx_vec_sve.c
+++ b/drivers/net/hns3/hns3_rxtx_vec_sve.c
@@ -454,14 +454,16 @@ hns3_xmit_fixed_burst_vec_sve(void *__restrict tx_queue,
 		return 0;
 	}
 
-	if (txq->next_to_use + nb_pkts > txq->nb_tx_desc) {
+	if (txq->next_to_use + nb_pkts >= txq->nb_tx_desc) {
 		nb_tx = txq->nb_tx_desc - txq->next_to_use;
 		hns3_tx_fill_hw_ring_sve(txq, tx_pkts, nb_tx);
 		txq->next_to_use = 0;
 	}
 
-	hns3_tx_fill_hw_ring_sve(txq, tx_pkts + nb_tx, nb_pkts - nb_tx);
-	txq->next_to_use += nb_pkts - nb_tx;
+	if (nb_pkts > nb_tx) {
+		hns3_tx_fill_hw_ring_sve(txq, tx_pkts + nb_tx, nb_pkts - nb_tx);
+		txq->next_to_use += nb_pkts - nb_tx;
+	}
 
 	txq->tx_bd_ready -= nb_pkts;
 	hns3_write_reg_opt(txq->io_tail_reg, nb_pkts);
-- 
2.34.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2022-11-03 09:27:29.718787706 +0000
+++ 0072-net-hns3-fix-next-to-use-overflow-in-SVE-Tx.patch	2022-11-03 09:27:25.501424919 +0000
@@ -1 +1 @@
-From 3efbc3c4027c87c14727a6a5ce13b099cd8d5866 Mon Sep 17 00:00:00 2001
+From cf08ee6b1f4a9d442b078e84e72d06f672b7833a Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 3efbc3c4027c87c14727a6a5ce13b099cd8d5866 ]
+
@@ -12 +13,0 @@
-Cc: stable at dpdk.org
@@ -21 +22 @@
-index b0dfb052bb..f09a81dbd5 100644
+index 67bf8ccdc5..e7446eb017 100644
@@ -24 +25 @@
-@@ -464,14 +464,16 @@ hns3_xmit_fixed_burst_vec_sve(void *__restrict tx_queue,
+@@ -454,14 +454,16 @@ hns3_xmit_fixed_burst_vec_sve(void *__restrict tx_queue,
@@ -43 +44 @@
- 	hns3_write_txq_tail_reg(txq, nb_pkts);
+ 	hns3_write_reg_opt(txq->io_tail_reg, nb_pkts);