patch 'net/ena: fix meta descriptor DF flag setup' has been queued to stable release 20.11.5

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 20.11.5

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 03/02/22. 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/bluca/dpdk-stable

This queued commit can be viewed at:
https://github.com/bluca/dpdk-stable/commit/abbaa0b9d15ab2e0598877bdea27ac0e00766413

Thanks.

Luca Boccassi

---
>From abbaa0b9d15ab2e0598877bdea27ac0e00766413 Mon Sep 17 00:00:00 2001
From: Michal Krawczyk <mk at semihalf.com>
Date: Wed, 23 Feb 2022 13:19:40 +0100
Subject: [PATCH] net/ena: fix meta descriptor DF flag setup

[ upstream commit 022fb61b62623868db2ec9dbe5b1ee43a4d6cbfb ]

Whenever Tx checksum offload is being used, the meta descriptor content
is taken into consideration. Setting DF field properly in the meta
descriptor may have huge impact on the performance both for the IPv4 and
IPv6 packets.

The requirements for the df field are as below:
* No offload used - value doesn't matter
* IPv4 - 0 or 1, depending on the DF flag in the IPv4 header
* IPv6 - 1

Setting DF to 0 causes the packet to enter the slow-path in the HW and
as a result can noticeable impact the performance.

Moreover, as 'true' may not always be mapped to 1 depending on it's
definition for the given platform/compiler, for safety DF field is being
set explicitly to 1.

Fixes: 1173fca25af9 ("ena: add polling-mode driver")

Signed-off-by: Michal Krawczyk <mk at semihalf.com>
Reviewed-by: Dawid Gorecki <dgr at semihalf.com>
Reviewed-by: Shai Brandes <shaibran at amazon.com>
---
 drivers/net/ena/ena_ethdev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index 13154602a2..f17679e3f8 100644
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -374,6 +374,8 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf,
 
 		if (mbuf->ol_flags & PKT_TX_IPV6) {
 			ena_tx_ctx->l3_proto = ENA_ETH_IO_L3_PROTO_IPV6;
+			/* For the IPv6 packets, DF always needs to be true. */
+			ena_tx_ctx->df = 1;
 		} else {
 			ena_tx_ctx->l3_proto = ENA_ETH_IO_L3_PROTO_IPV4;
 
@@ -381,7 +383,7 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf,
 			if (mbuf->packet_type &
 				(RTE_PTYPE_L4_NONFRAG
 				 | RTE_PTYPE_INNER_L4_NONFRAG))
-				ena_tx_ctx->df = true;
+				ena_tx_ctx->df = 1;
 		}
 
 		/* check if L4 checksum is needed */
-- 
2.30.2

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2022-02-28 21:17:57.004018379 +0000
+++ 0038-net-ena-fix-meta-descriptor-DF-flag-setup.patch	2022-02-28 21:17:54.000932737 +0000
@@ -1 +1 @@
-From 022fb61b62623868db2ec9dbe5b1ee43a4d6cbfb Mon Sep 17 00:00:00 2001
+From abbaa0b9d15ab2e0598877bdea27ac0e00766413 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 022fb61b62623868db2ec9dbe5b1ee43a4d6cbfb ]
+
@@ -24 +25,0 @@
-Cc: stable at dpdk.org
@@ -34 +35 @@
-index 0ca4269522..53a8071968 100644
+index 13154602a2..f17679e3f8 100644
@@ -37 +38 @@
-@@ -624,6 +624,8 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf,
+@@ -374,6 +374,8 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf,
@@ -39 +40 @@
- 		if (mbuf->ol_flags & RTE_MBUF_F_TX_IPV6) {
+ 		if (mbuf->ol_flags & PKT_TX_IPV6) {
@@ -46 +47 @@
-@@ -631,7 +633,7 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf,
+@@ -381,7 +383,7 @@ static inline void ena_tx_mbuf_prepare(struct rte_mbuf *mbuf,