patch 'net/mlx5: fix inline length exceeding descriptor limit' 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/e577d667725a70e02d45e20199427aabbf52fea4

Thanks.

Luca Boccassi

---
>From e577d667725a70e02d45e20199427aabbf52fea4 Mon Sep 17 00:00:00 2001
From: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
Date: Wed, 17 Aug 2022 17:13:57 +0300
Subject: [PATCH] net/mlx5: fix inline length exceeding descriptor limit

[ upstream commit d15bfd2930f343baf3f9e3a20b6d5f948f783394 ]

The hardware descriptor (WQE) length field is 6 bits wide
and we have the native limitation for the overall descriptor
length. To improve the PCIe bandwidth the packet data can be
inline into descriptor. If PMD was configured to inline large
amount of data it happened there was no enough space remaining
in the descriptor to specify all the packet data segments and
PMD rejected problematic packets.

The patch tries to adjust the inline data length conservatively
and allows to avoid error occurring.

Fixes: 18a1c20044c0 ("net/mlx5: implement Tx burst template")
Fixes: e2259f93ef45 ("net/mlx5: fix Tx when inlining is impossible")

Signed-off-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
Reviewed-by: Dmitry Kozlyuk <dkozlyuk at nvidia.com>
---
 drivers/net/mlx5/mlx5_rxtx.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 1ba70264c8..436c207281 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -3575,8 +3575,24 @@ do_build:
 	if (unlikely(loc->wqe_free < ((ds + 3) / 4)))
 		return MLX5_TXCMP_CODE_EXIT;
 	/* Check for maximal WQE size. */
-	if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ds))
-		return MLX5_TXCMP_CODE_ERROR;
+	if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ds)) {
+		/*  Check if we can adjust the inline length. */
+		if (unlikely(txq->inlen_mode)) {
+			ds = NB_SEGS(loc->mbuf) + 2 +
+				(txq->inlen_mode -
+				MLX5_ESEG_MIN_INLINE_SIZE +
+				MLX5_WSEG_SIZE +
+				MLX5_WSEG_SIZE - 1) / MLX5_WSEG_SIZE;
+			if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ds))
+				return MLX5_TXCMP_CODE_ERROR;
+		}
+		/* We have lucky opportunity to adjust. */
+		inlen = RTE_MIN(inlen, MLX5_WQE_SIZE_MAX -
+				       MLX5_WSEG_SIZE * 2 -
+				       MLX5_WSEG_SIZE * NB_SEGS(loc->mbuf) -
+				       MLX5_WSEG_SIZE +
+				       MLX5_ESEG_MIN_INLINE_SIZE);
+	}
 #ifdef MLX5_PMD_SOFT_COUNTERS
 	/* Update sent data bytes/packets counters. */
 	txq->stats.obytes += dlen + vlan;
-- 
2.34.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2022-11-03 09:27:28.219081693 +0000
+++ 0046-net-mlx5-fix-inline-length-exceeding-descriptor-limi.patch	2022-11-03 09:27:25.429423524 +0000
@@ -1 +1 @@
-From d15bfd2930f343baf3f9e3a20b6d5f948f783394 Mon Sep 17 00:00:00 2001
+From e577d667725a70e02d45e20199427aabbf52fea4 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit d15bfd2930f343baf3f9e3a20b6d5f948f783394 ]
+
@@ -19 +20,0 @@
-Cc: stable at dpdk.org
@@ -24 +25 @@
- drivers/net/mlx5/mlx5_tx.h | 20 ++++++++++++++++++--
+ drivers/net/mlx5/mlx5_rxtx.c | 20 ++++++++++++++++++--
@@ -27,5 +28,5 @@
-diff --git a/drivers/net/mlx5/mlx5_tx.h b/drivers/net/mlx5/mlx5_tx.h
-index 8e113e3778..59ebe95032 100644
---- a/drivers/net/mlx5/mlx5_tx.h
-+++ b/drivers/net/mlx5/mlx5_tx.h
-@@ -2078,8 +2078,24 @@ do_build:
+diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
+index 1ba70264c8..436c207281 100644
+--- a/drivers/net/mlx5/mlx5_rxtx.c
++++ b/drivers/net/mlx5/mlx5_rxtx.c
+@@ -3575,8 +3575,24 @@ do_build: