Commit 22fdf28f authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Jakub Kicinski
Browse files

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. Cover channel resize paths (both
netlink and ioctl) to reject resizing when the queues would be affected.

Given we need to have different checks for RX vs TX, detangle the code into
a two-loop version rather than the range of new_combined + min(new_rx, new_tx)
to old_combined + max(old_rx, old_tx).

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Co-developed-by: default avatarDavid Wei <dw@davidwei.uk>
Signed-off-by: default avatarDavid Wei <dw@davidwei.uk>
Reviewed-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260402231031.447597-5-daniel@iogearbox.net


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 21d58b35

net/ethtool/channels.c

+17 −11
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only



#include <net/xdp_sock_drv.h>

#include <net/netdev_queues.h>



#include "common.h"

#include "netlink.h"
@@ -109,7 +109,7 @@ ethnl_set_channels_validate(struct ethnl_req_info *req_info, 
static int

ethnl_set_channels(struct ethnl_req_info *req_info, struct genl_info *info)

{

	unsigned int from_channel, old_total, i;

	unsigned int old_combined, old_rx, old_tx, i;

	bool mod = false, mod_combined = false;

	struct net_device *dev = req_info->dev;

	struct ethtool_channels channels = {};
@@ -118,8 +118,9 @@ ethnl_set_channels(struct ethnl_req_info *req_info, struct genl_info *info) 
	int ret;



	dev->ethtool_ops->get_channels(dev, &channels);

	old_total = channels.combined_count +

		    max(channels.rx_count, channels.tx_count);

	old_combined = channels.combined_count;

	old_rx = channels.rx_count;

	old_tx = channels.tx_count;



	ethnl_update_u32(&channels.rx_count, tb[ETHTOOL_A_CHANNELS_RX_COUNT],

			 &mod);
@@ -169,12 +170,17 @@ 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 */

	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");

	/* ensure channels are not busy at the moment */

	for (i = channels.combined_count + channels.rx_count;

	     i < old_combined + old_rx; i++) {

		if (netdev_queue_busy(dev, i, NETDEV_QUEUE_TYPE_RX,

				      info->extack))

			return -EINVAL;

	}

	for (i = channels.combined_count + channels.tx_count;

	     i < old_combined + old_tx; i++) {

		if (netdev_queue_busy(dev, i, NETDEV_QUEUE_TYPE_TX,

				      info->extack))

			return -EINVAL;

	}

net/ethtool/ioctl.c

+12 −9
Original line number Diff line number Diff line
@@ -27,12 +27,12 @@ 
#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"
@@ -2250,7 +2250,6 @@ static noinline_for_stack int ethtool_set_channels(struct net_device *dev, 
						   void __user *useraddr)

{

	struct ethtool_channels channels, curr = { .cmd = ETHTOOL_GCHANNELS };

	u16 from_channel, to_channel;

	unsigned int i;

	int ret;
@@ -2284,13 +2283,17 @@ static noinline_for_stack int ethtool_set_channels(struct net_device *dev, 
	if (ret)

		return ret;



	/* Disabling channels, query zero-copy AF_XDP sockets */

	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))

	/* Disabling channels, query busy queues (AF_XDP, queue leasing) */

	for (i = channels.combined_count + channels.rx_count;

	     i < curr.combined_count + curr.rx_count; i++) {

		if (netdev_queue_busy(dev, i, NETDEV_QUEUE_TYPE_RX, NULL))

			return -EINVAL;

	}

	for (i = channels.combined_count + channels.tx_count;

	     i < curr.combined_count + curr.tx_count; i++) {

		if (netdev_queue_busy(dev, i, NETDEV_QUEUE_TYPE_TX, NULL))

			return -EINVAL;

	}



	ret = dev->ethtool_ops->set_channels(dev, &channels);

	if (!ret)