patch 'net/mlx5: fix maximum packet headers size for TSO' has been queued to stable release 19.11.12

[christian.ehrhardt@canonical.com]

Hi,

FYI, your patch has been queued to stable release 19.11.12

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 02/27/22. 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/cpaelzer/dpdk-stable-queue

This queued commit can be viewed at:
https://github.com/cpaelzer/dpdk-stable-queue/commit/6edb22f2d81bb8318dd25b9fcd2aaeeecc92863c

Thanks.

Christian Ehrhardt <christian.ehrhardt@canonical.com>

---
From 6edb22f2d81bb8318dd25b9fcd2aaeeecc92863c Mon Sep 17 00:00:00 2001
From: Alexander Kozyrev <akozyrev@nvidia.com>
Date: Thu, 13 Jan 2022 16:32:29 +0200
Subject: [PATCH] net/mlx5: fix maximum packet headers size for TSO

[ upstream commit 9701034faab0f84ba42e1f5343afda5464b11ca3 ]

The maximum packet headers size for TSO is calculated as a sum of
Ethernet, VLAN, IPv6 and TCP headers (plus inner headers).
The rationale  behind choosing IPv6 and TCP is their headers
are bigger than IPv4 and UDP respectively, giving us the maximum
possible headers size. But it is not true for L3 headers.
IPv4 header size (20 bytes) is smaller than IPv6 header size
(40 bytes) only in the default case. There are up to 10
optional header fields called Options in case IHL > 5.
This means that the maximum size of the IPv4 header is 60 bytes.

Choosing the wrong maximum packets headers size causes inability
to transmit multi-segment TSO packets with IPv4 Options present.
PMD check that it is possible to inline all the packet headers
and the packet headers size exceeds the expected maximum size.
The maximum packet headers size was set to 192 bytes before,
but its value has been reduced during Tx path refactor activity.
Restore the proper maximum packet headers size for TSO.

Fixes: 50724e1bba76 ("net/mlx5: update Tx definitions")

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
 drivers/net/mlx5/mlx5_defs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/mlx5/mlx5_defs.h b/drivers/net/mlx5/mlx5_defs.h
index 2836099b75..b1c72714bf 100644
--- a/drivers/net/mlx5/mlx5_defs.h
+++ b/drivers/net/mlx5/mlx5_defs.h
@@ -70,7 +70,7 @@
 #define MLX5_MAX_XSTATS 32
 
 /* Maximum Packet headers size (L2+L3+L4) for TSO. */
-#define MLX5_MAX_TSO_HEADER (128u + 34u)
+#define MLX5_MAX_TSO_HEADER 192U
 
 /* Inline data size required by NICs. */
 #define MLX5_INLINE_HSIZE_NONE 0
-- 
2.35.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2022-02-25 16:58:44.918270261 +0100
+++ 0016-net-mlx5-fix-maximum-packet-headers-size-for-TSO.patch	2022-02-25 16:58:44.216990391 +0100
@@ -1 +1 @@
-From 9701034faab0f84ba42e1f5343afda5464b11ca3 Mon Sep 17 00:00:00 2001
+From 6edb22f2d81bb8318dd25b9fcd2aaeeecc92863c Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 9701034faab0f84ba42e1f5343afda5464b11ca3 ]
+
@@ -25 +26,0 @@
-Cc: stable@dpdk.org
@@ -34 +35 @@
-index 36b384fa08..2d48fde010 100644
+index 2836099b75..b1c72714bf 100644
@@ -37 +38 @@
-@@ -50,7 +50,7 @@
+@@ -70,7 +70,7 @@