patch 'net/bonding: clamp Rx free threshold for small rings' has been queued to stable release 25.11.1

[Kevin Traynor]

Hi,

FYI, your patch has been queued to stable release 25.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 03/23/26. 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/b5e7d9b1bb99126fa20b57ced677468556f505dd

Thanks.

Kevin

---
>From b5e7d9b1bb99126fa20b57ced677468556f505dd Mon Sep 17 00:00:00 2001
From: Bruce Richardson <bruce.richardson at intel.com>
Date: Tue, 24 Feb 2026 12:13:58 +0000
Subject: [PATCH] net/bonding: clamp Rx free threshold for small rings
MIME-Version: 1.0
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[ upstream commit db0d974a19cda17fa88896412fc0bcecb6d8a6a3 ]

The bonding driver creates a minimal-sized Rx ring as part of the setup,
using the driver default parameters as it does so. However, for some
cases the default values need adjustment for absolute minimal sized
rings which can cause failures - for example, having an free threshold
of 32 is too large for a ring of size 64.

Unfortunately, the drivers themselves cannot properly handle this by
adjusting their defaults because:
a) the defaults are returned from info_get which gets called before the
desired ring-size is known
b) the replacement of the NULL rxconf value, which indicates use of
defaults, happens at the ethdev level, so the driver is unaware of the
source of the requested parameters - whether they are explicitly set by
the user or substituted by ethdev layer.

Therefore, we modify the bonding PMD to clamp the free thresh value to
ring_size / 4 which should work in all cases.

Fixes: 4da0705bf896 ("net/bonding: fix dedicated queue setup")

Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
Acked-by: Morten Brørup <mb at smartsharesystems.com>
---
 drivers/net/bonding/rte_eth_bond_pmd.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/rte_eth_bond_pmd.c b/drivers/net/bonding/rte_eth_bond_pmd.c
index b7bab6bc99..96725071da 100644
--- a/drivers/net/bonding/rte_eth_bond_pmd.c
+++ b/drivers/net/bonding/rte_eth_bond_pmd.c
@@ -1702,9 +1702,16 @@ member_configure_slow_queue(struct rte_eth_dev *bonding_eth_dev,
 			nb_rx_desc = member_info.rx_desc_lim.nb_min;
 
-		/* Configure slow Rx queue */
+		/* Configure slow Rx queue.
+		 * Use explicit conf rather than NULL so we can clamp rx_free_thresh:
+		 * with a minimum-sized ring the default rx_free_thresh may be too large
+		 * for some drivers to work correctly, so clamp it to ring_size / 4.
+		 */
+		struct rte_eth_rxconf slow_rx_conf = member_info.default_rxconf;
+		if (slow_rx_conf.rx_free_thresh > nb_rx_desc / 4)
+			slow_rx_conf.rx_free_thresh = nb_rx_desc / 4;
 		errval = rte_eth_rx_queue_setup(member_eth_dev->data->port_id,
 				internals->mode4.dedicated_queues.rx_qid, nb_rx_desc,
 				rte_eth_dev_socket_id(member_eth_dev->data->port_id),
-				NULL, port->slow_pool);
+				&slow_rx_conf, port->slow_pool);
 		if (errval != 0) {
 			RTE_BOND_LOG(ERR,
-- 
2.53.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2026-03-19 10:01:08.352340071 +0000
+++ 0042-net-bonding-clamp-Rx-free-threshold-for-small-rings.patch	2026-03-19 10:01:07.108331261 +0000
@@ -1 +1 @@
-From db0d974a19cda17fa88896412fc0bcecb6d8a6a3 Mon Sep 17 00:00:00 2001
+From b5e7d9b1bb99126fa20b57ced677468556f505dd Mon Sep 17 00:00:00 2001
@@ -8,0 +9,2 @@
+[ upstream commit db0d974a19cda17fa88896412fc0bcecb6d8a6a3 ]
+
@@ -28 +29,0 @@
-Cc: stable at dpdk.org