netdev - [PATCH net-next v5 04/16] net, ethtool: Disallow leased real rxqs to be resized

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Message-ID: <20260109212632.146920-5-daniel@iogearbox.net>
Date: Fri,  9 Jan 2026 22:26:20 +0100
From: Daniel Borkmann <daniel@...earbox.net>
To: netdev@...r.kernel.org
Cc: bpf@...r.kernel.org,
	kuba@...nel.org,
	davem@...emloft.net,
	razor@...ckwall.org,
	pabeni@...hat.com,
	willemb@...gle.com,
	sdf@...ichev.me,
	john.fastabend@...il.com,
	martin.lau@...nel.org,
	jordan@...fe.io,
	maciej.fijalkowski@...el.com,
	magnus.karlsson@...el.com,
	dw@...idwei.uk,
	toke@...hat.com,
	yangzhenze@...edance.com,
	wangdongdong.6@...edance.com
Subject: [PATCH net-next v5 04/16] 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@...earbox.net>
Co-developed-by: David Wei <dw@...idwei.uk>
Signed-off-by: David Wei <dw@...idwei.uk>
Reviewed-by: Nikolay Aleksandrov <razor@...ckwall.org>
---
 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 ca4f80282448..797d2a08c515 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 9431e305b233..02a3454234d6 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);
-- 
2.43.0