[dpdk-stable] patch 'app/testpmd: fix MTU after device configure' has been queued to stable release 19.11.6

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 19.11.6

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/19/20. 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/3c70f73579e1da8b53853f2c8379eaeb997ae40e

Thanks.

Luca Boccassi

---
>From 3c70f73579e1da8b53853f2c8379eaeb997ae40e Mon Sep 17 00:00:00 2001
From: Ferruh Yigit <ferruh.yigit at intel.com>
Date: Fri, 13 Nov 2020 11:44:00 +0000
Subject: [PATCH] app/testpmd: fix MTU after device configure

[ upstream commit 1c21ee95cf5298fe7b6a8b7d8a997ff3c402a08f ]

In 'rte_eth_dev_configure()', if 'DEV_RX_OFFLOAD_JUMBO_FRAME' is not set
the max frame size is limited to 'RTE_ETHER_MAX_LEN' (1518).
This is mistake because for the PMDs that has frame size bigger than
"RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN" (18 bytes), the MTU becomes
less than 1500, causing a valid frame with 1500 bytes payload to be
dropped.

Since 'rte_eth_dev_set_mtu()' works as expected, it is called after
'rte_eth_dev_configure()' to fix the MTU.
It may look redundant to set MTU after 'rte_eth_dev_configure()', both
with default values, but it is not, the resulting MTU config can be
different in the device based on frame overhead of the PMD.

And instead of setting the MTU to default value, it is first get via
'rte_eth_dev_get_mtu()' and set again, this is to cover cases MTU
changed from testpmd command line.

'rte_eth_dev_set_mtu()', '-ENOTSUP' error is ignored to prevent
irrelevant warning messages for the virtual PMDs.

Fixes: af75078fece3 ("first public release")

Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>
Reviewed-by: Qi Zhang <qi.z.zhang at intel.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>
Tested-by: Igor Romanov <igor.romanov at oktetlabs.ru>
---
 app/test-pmd/testpmd.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 8d3b7b2a3b..7b08bd2f59 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -2334,6 +2334,8 @@ start_port(portid_t pid)
 		}
 
 		if (port->need_reconfig > 0) {
+			uint16_t mtu = RTE_ETHER_MTU;
+
 			port->need_reconfig = 0;
 
 			if (flow_isolate_all) {
@@ -2367,6 +2369,23 @@ start_port(portid_t pid)
 				port->need_reconfig = 1;
 				return -1;
 			}
+
+			/*
+			 * Workaround for rte_eth_dev_configure(), max_rx_pkt_len
+			 * set MTU wrong for the PMDs that have frame overhead
+			 * bigger than RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN.
+			 * For a PMD that has 26 bytes overhead, rte_eth_dev_configure()
+			 * can set MTU to max 1492, not to expected 1500 bytes.
+			 * Using rte_eth_dev_set_mtu() to be able to set MTU correctly,
+			 * default MTU value is 1500.
+			 */
+			diag = rte_eth_dev_get_mtu(pi, &mtu);
+			if (diag)
+				printf("Failed to get MTU for port %d\n", pi);
+			diag = rte_eth_dev_set_mtu(pi, mtu);
+			if (diag != 0 && diag != -ENOTSUP)
+				printf("Failed to set MTU to %u for port %d\n",
+						mtu, pi);
 		}
 		if (port->need_reconfig_queues > 0) {
 			port->need_reconfig_queues = 0;
-- 
2.27.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-11-17 11:13:14.293311684 +0000
+++ 0031-app-testpmd-fix-MTU-after-device-configure.patch	2020-11-17 11:13:12.941117012 +0000
@@ -1 +1 @@
-From 1c21ee95cf5298fe7b6a8b7d8a997ff3c402a08f Mon Sep 17 00:00:00 2001
+From 3c70f73579e1da8b53853f2c8379eaeb997ae40e Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 1c21ee95cf5298fe7b6a8b7d8a997ff3c402a08f ]
+
@@ -27 +28,0 @@
-Cc: stable at dpdk.org
@@ -38 +39 @@
-index 33fc0fddf5..48e9647fc7 100644
+index 8d3b7b2a3b..7b08bd2f59 100644
@@ -41 +42 @@
-@@ -2537,6 +2537,8 @@ start_port(portid_t pid)
+@@ -2334,6 +2334,8 @@ start_port(portid_t pid)
@@ -50 +51 @@
-@@ -2570,6 +2572,23 @@ start_port(portid_t pid)
+@@ -2367,6 +2369,23 @@ start_port(portid_t pid)