Commit e19c591e authored by Michal Kubecek's avatar Michal Kubecek Committed by David S. Miller
Browse files

ethtool: set device channel counts with CHANNELS_SET request 



Implement CHANNELS_SET netlink request to set channel counts of a network
device. These are traditionally set with ETHTOOL_SCHANNELS ioctl request.

Like the ioctl implementation, the generic ethtool code checks if supplied
values do not exceed driver defined limits; if they do, first offending
attribute is reported using extack. Checks preventing removing channels
used for RX indirection table or zerocopy AF_XDP socket are also
implemented.

Move ethtool_get_max_rxfh_channel() helper into common.c so that it can be
used by both ioctl and netlink code.

v2:
  - fix netdev reference leak in error path (found by Jakub Kicinsky)

Signed-off-by: default avatarMichal Kubecek <mkubecek@suse.cz>
Reviewed-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0c84979c

Documentation/networking/ethtool-netlink.rst

+22 −1
Original line number Diff line number Diff line
@@ -196,6 +196,7 @@ Userspace to kernel: 
  ``ETHTOOL_MSG_RINGS_GET``             get ring sizes

  ``ETHTOOL_MSG_RINGS_SET``             set ring sizes

  ``ETHTOOL_MSG_CHANNELS_GET``          get channel counts

  ``ETHTOOL_MSG_CHANNELS_SET``          set channel counts

  ===================================== ================================



Kernel to userspace:
@@ -723,6 +724,26 @@ Kernel response contents: 
  =====================================  ======  ==========================





CHANNELS_SET

============



Sets channel counts like ``ETHTOOL_SCHANNELS`` ioctl request.



Request contents:



  =====================================  ======  ==========================

  ``ETHTOOL_A_CHANNELS_HEADER``          nested  request header

  ``ETHTOOL_A_CHANNELS_RX_COUNT``        u32     receive channel count

  ``ETHTOOL_A_CHANNELS_TX_COUNT``        u32     transmit channel count

  ``ETHTOOL_A_CHANNELS_OTHER_COUNT``     u32     other channel count

  ``ETHTOOL_A_CHANNELS_COMBINED_COUNT``  u32     combined channel count

  =====================================  ======  ==========================



Kernel checks that requested channel counts do not exceed limits reported by

driver. Driver may impose additional constraints and may not suspport all

attributes.





Request translation

===================
@@ -794,7 +815,7 @@ have their netlink replacement yet. 
  ``ETHTOOL_GFEATURES``               ``ETHTOOL_MSG_FEATURES_GET``

  ``ETHTOOL_SFEATURES``               ``ETHTOOL_MSG_FEATURES_SET``

  ``ETHTOOL_GCHANNELS``               ``ETHTOOL_MSG_CHANNELS_GET``

  ``ETHTOOL_SCHANNELS``               n/a

  ``ETHTOOL_SCHANNELS``               ``ETHTOOL_MSG_CHANNELS_SET``

  ``ETHTOOL_SET_DUMP``                n/a

  ``ETHTOOL_GET_DUMP_FLAG``           n/a

  ``ETHTOOL_GET_DUMP_DATA``           n/a

include/uapi/linux/ethtool_netlink.h

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ enum { 
	ETHTOOL_MSG_RINGS_GET,

	ETHTOOL_MSG_RINGS_SET,

	ETHTOOL_MSG_CHANNELS_GET,

	ETHTOOL_MSG_CHANNELS_SET,



	/* add new constants above here */

	__ETHTOOL_MSG_USER_CNT,

net/ethtool/channels.c

+116 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only



#include <net/xdp_sock.h>



#include "netlink.h"

#include "common.h"
@@ -106,3 +108,117 @@ const struct ethnl_request_ops ethnl_channels_request_ops = { 
	.reply_size		= channels_reply_size,

	.fill_reply		= channels_fill_reply,

};



/* CHANNELS_SET */



static const struct nla_policy

channels_set_policy[ETHTOOL_A_CHANNELS_MAX + 1] = {

	[ETHTOOL_A_CHANNELS_UNSPEC]		= { .type = NLA_REJECT },

	[ETHTOOL_A_CHANNELS_HEADER]		= { .type = NLA_NESTED },

	[ETHTOOL_A_CHANNELS_RX_MAX]		= { .type = NLA_REJECT },

	[ETHTOOL_A_CHANNELS_TX_MAX]		= { .type = NLA_REJECT },

	[ETHTOOL_A_CHANNELS_OTHER_MAX]		= { .type = NLA_REJECT },

	[ETHTOOL_A_CHANNELS_COMBINED_MAX]	= { .type = NLA_REJECT },

	[ETHTOOL_A_CHANNELS_RX_COUNT]		= { .type = NLA_U32 },

	[ETHTOOL_A_CHANNELS_TX_COUNT]		= { .type = NLA_U32 },

	[ETHTOOL_A_CHANNELS_OTHER_COUNT]	= { .type = NLA_U32 },

	[ETHTOOL_A_CHANNELS_COMBINED_COUNT]	= { .type = NLA_U32 },

};



int ethnl_set_channels(struct sk_buff *skb, struct genl_info *info)

{

	struct nlattr *tb[ETHTOOL_A_CHANNELS_MAX + 1];

	unsigned int from_channel, old_total, i;

	struct ethtool_channels channels = {};

	struct ethnl_req_info req_info = {};

	const struct nlattr *err_attr;

	const struct ethtool_ops *ops;

	struct net_device *dev;

	u32 max_rx_in_use = 0;

	bool mod = false;

	int ret;



	ret = nlmsg_parse(info->nlhdr, GENL_HDRLEN, tb,

			  ETHTOOL_A_CHANNELS_MAX, channels_set_policy,

			  info->extack);

	if (ret < 0)

		return ret;

	ret = ethnl_parse_header_dev_get(&req_info,

					 tb[ETHTOOL_A_CHANNELS_HEADER],

					 genl_info_net(info), info->extack,

					 true);

	if (ret < 0)

		return ret;

	dev = req_info.dev;

	ops = dev->ethtool_ops;

	ret = -EOPNOTSUPP;

	if (!ops->get_channels || !ops->set_channels)

		goto out_dev;



	rtnl_lock();

	ret = ethnl_ops_begin(dev);

	if (ret < 0)

		goto out_rtnl;

	ops->get_channels(dev, &channels);

	old_total = channels.combined_count +

		    max(channels.rx_count, channels.tx_count);



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

			 &mod);

	ethnl_update_u32(&channels.tx_count, tb[ETHTOOL_A_CHANNELS_TX_COUNT],

			 &mod);

	ethnl_update_u32(&channels.other_count,

			 tb[ETHTOOL_A_CHANNELS_OTHER_COUNT], &mod);

	ethnl_update_u32(&channels.combined_count,

			 tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT], &mod);

	ret = 0;

	if (!mod)

		goto out_ops;



	/* ensure new channel counts are within limits */

	if (channels.rx_count > channels.max_rx)

		err_attr = tb[ETHTOOL_A_CHANNELS_RX_COUNT];

	else if (channels.tx_count > channels.max_tx)

		err_attr = tb[ETHTOOL_A_CHANNELS_TX_COUNT];

	else if (channels.other_count > channels.max_other)

		err_attr = tb[ETHTOOL_A_CHANNELS_OTHER_COUNT];

	else if (channels.combined_count > channels.max_combined)

		err_attr = tb[ETHTOOL_A_CHANNELS_COMBINED_COUNT];

	else

		err_attr = NULL;

	if (err_attr) {

		ret = -EINVAL;

		NL_SET_ERR_MSG_ATTR(info->extack, err_attr,

				    "requested channel count exceeeds maximum");

		goto out_ops;

	}



	/* ensure the new Rx count fits within the configured Rx flow

	 * indirection table settings

	 */

	if (netif_is_rxfh_configured(dev) &&

	    !ethtool_get_max_rxfh_channel(dev, &max_rx_in_use) &&

	    (channels.combined_count + channels.rx_count) <= max_rx_in_use) {

		GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing indirection table settings");

		return -EINVAL;

	}



	/* 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 (xdp_get_umem_from_qid(dev, i)) {

			GENL_SET_ERR_MSG(info, "requested channel counts are too low for existing zerocopy AF_XDP sockets");

			return -EINVAL;

		}



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



out_ops:

	ethnl_ops_complete(dev);

out_rtnl:

	rtnl_unlock();

out_dev:

	dev_put(dev);

	return ret;

}

net/ethtool/common.c

+31 −0
Original line number Diff line number Diff line
@@ -258,3 +258,34 @@ int __ethtool_get_link(struct net_device *dev) 


	return netif_running(dev) && dev->ethtool_ops->get_link(dev);

}



int ethtool_get_max_rxfh_channel(struct net_device *dev, u32 *max)

{

	u32 dev_size, current_max = 0;

	u32 *indir;

	int ret;



	if (!dev->ethtool_ops->get_rxfh_indir_size ||

	    !dev->ethtool_ops->get_rxfh)

		return -EOPNOTSUPP;

	dev_size = dev->ethtool_ops->get_rxfh_indir_size(dev);

	if (dev_size == 0)

		return -EOPNOTSUPP;



	indir = kcalloc(dev_size, sizeof(indir[0]), GFP_USER);

	if (!indir)

		return -ENOMEM;



	ret = dev->ethtool_ops->get_rxfh(dev, indir, NULL, NULL);

	if (ret)

		goto out;



	while (dev_size--)

		current_max = max(current_max, indir[dev_size]);



	*max = current_max;



out:

	kfree(indir);

	return ret;

}

net/ethtool/common.h

+1 −0
Original line number Diff line number Diff line
@@ -29,5 +29,6 @@ int __ethtool_get_link(struct net_device *dev); 
bool convert_legacy_settings_to_link_ksettings(

	struct ethtool_link_ksettings *link_ksettings,

	const struct ethtool_cmd *legacy_settings);

int ethtool_get_max_rxfh_channel(struct net_device *dev, u32 *max);



#endif /* _ETHTOOL_COMMON_H */

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