From ff8889ff9107f01346ba0d2e580ecadfa5fac5c5 Mon Sep 17 00:00:00 2001
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 15 Jan 2026 09:25:51 +0100
Subject: [PATCH] net, ethtool: Disallow leased real rxqs to be resized

Similar to AF_XDP, do not allow queues in a physical netdev to be
resized by ethtool -L when they are leased.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20260115082603.219152-5-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/ethtool/channels.c | 12 +++++++-----
 net/ethtool/ioctl.c    |  9 +++++----
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/net/ethtool/channels.c b/net/ethtool/channels.c
index ca4f80282448b..797d2a08c5153 100644
--- a/net/ethtool/channels.c
+++ b/net/ethtool/channels.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
-#include <net/xdp_sock_drv.h>
+#include <net/netdev_queues.h>
 
 #include "netlink.h"
 #include "common.h"
@@ -169,14 +169,16 @@ ethnl_set_channels(struct ethnl_req_info *req_info, struct genl_info *info)
 	if (ret)
 		return ret;
 
-	/* Disabling channels, query zero-copy AF_XDP sockets */
+	/* ensure channels are not busy at the moment */
 	from_channel = channels.combined_count +
 		       min(channels.rx_count, channels.tx_count);
-	for (i = from_channel; i < old_total; i++)
-		if (xsk_get_pool_from_qid(dev, i)) {
-			GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing zerocopy AF_XDP sockets");
+	for (i = from_channel; i < old_total; i++) {
+		if (netdev_queue_busy(dev, i, NULL)) {
+			GENL_SET_ERR_MSG(info,
+					 "requested channel counts are too low due to busy queues (AF_XDP or queue leasing)");
 			return -EINVAL;
 		}
+	}
 
 	ret = dev->ethtool_ops->set_channels(dev, &channels);
 	return ret < 0 ? ret : 1;
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 9431e305b2333..02a3454234d6b 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -27,12 +27,13 @@
 #include <linux/net.h>
 #include <linux/pm_runtime.h>
 #include <linux/utsname.h>
+#include <linux/ethtool_netlink.h>
 #include <net/devlink.h>
 #include <net/ipv6.h>
-#include <net/xdp_sock_drv.h>
 #include <net/flow_offload.h>
 #include <net/netdev_lock.h>
-#include <linux/ethtool_netlink.h>
+#include <net/netdev_queues.h>
+
 #include "common.h"
 
 /* State held across locks and calls for commands which have devlink fallback */
@@ -2282,12 +2283,12 @@ static noinline_for_stack int ethtool_set_channels(struct net_device *dev,
 	if (ret)
 		return ret;
 
-	/* Disabling channels, query zero-copy AF_XDP sockets */
+	/* Disabling channels, query busy queues (AF_XDP, queue leasing) */
 	from_channel = channels.combined_count +
 		min(channels.rx_count, channels.tx_count);
 	to_channel = curr.combined_count + max(curr.rx_count, curr.tx_count);
 	for (i = from_channel; i < to_channel; i++)
-		if (xsk_get_pool_from_qid(dev, i))
+		if (netdev_queue_busy(dev, i, NULL))
 			return -EINVAL;
 
 	ret = dev->ethtool_ops->set_channels(dev, &channels);
-- 
2.47.3