dev.c

	return ret;
}
EXPORT_SYMBOL(dev_alloc_name);

static int dev_alloc_name_ns(struct net *net,
			     struct net_device *dev,
			     const char *name)
{
	char buf[IFNAMSIZ];
	int ret;

	ret = __dev_alloc_name(net, name, buf);
	if (ret >= 0)
		strlcpy(dev->name, buf, IFNAMSIZ);
	return ret;
}

static int dev_get_valid_name(struct net *net,
			      struct net_device *dev,
			      const char *name)
{
	BUG_ON(!net);

	if (!dev_valid_name(name))
		return -EINVAL;

	if (strchr(name, '%'))
		return dev_alloc_name_ns(net, dev, name);
	else if (__dev_get_by_name(net, name))
		return -EEXIST;
	else if (dev->name != name)
		strlcpy(dev->name, name, IFNAMSIZ);

	return 0;
}

/**
 *	dev_change_name - change name of a device
 *	@dev: device
 *	@newname: name (or format string) must be at least IFNAMSIZ
 *
 *	Change name of a device, can pass format strings "eth%d".
 *	for wildcarding.
 */
int dev_change_name(struct net_device *dev, const char *newname)
{
	char oldname[IFNAMSIZ];
	int err = 0;
	int ret;
	struct net *net;

	ASSERT_RTNL();
	BUG_ON(!dev_net(dev));

	net = dev_net(dev);
	if (dev->flags & IFF_UP)
		return -EBUSY;

	write_seqcount_begin(&devnet_rename_seq);

	if (strncmp(newname, dev->name, IFNAMSIZ) == 0) {
		write_seqcount_end(&devnet_rename_seq);
		return 0;
	}

	memcpy(oldname, dev->name, IFNAMSIZ);

	err = dev_get_valid_name(net, dev, newname);
	if (err < 0) {
		write_seqcount_end(&devnet_rename_seq);
		return err;
	}

rollback:
	ret = device_rename(&dev->dev, dev->name);
	if (ret) {
		memcpy(dev->name, oldname, IFNAMSIZ);
		write_seqcount_end(&devnet_rename_seq);
		return ret;
	}

	write_seqcount_end(&devnet_rename_seq);

	write_lock_bh(&dev_base_lock);
	hlist_del_rcu(&dev->name_hlist);
	write_unlock_bh(&dev_base_lock);

	synchronize_rcu();

	write_lock_bh(&dev_base_lock);
	hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name));
	write_unlock_bh(&dev_base_lock);

	ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev);
	ret = notifier_to_errno(ret);

	if (ret) {
		/* err >= 0 after dev_alloc_name() or stores the first errno */
		if (err >= 0) {
			err = ret;
			write_seqcount_begin(&devnet_rename_seq);
			memcpy(dev->name, oldname, IFNAMSIZ);
			goto rollback;
		} else {
			pr_err("%s: name change rollback failed: %d\n",
			       dev->name, ret);
		}
	}

	return err;
}

/**
 *	dev_set_alias - change ifalias of a device
 *	@dev: device
 *	@alias: name up to IFALIASZ
 *	@len: limit of bytes to copy from info
 *
 *	Set ifalias for a device,
 */
int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
{
	char *new_ifalias;

	ASSERT_RTNL();

	if (len >= IFALIASZ)
		return -EINVAL;

	if (!len) {
		kfree(dev->ifalias);
		dev->ifalias = NULL;
		return 0;
	}

	new_ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL);
	if (!new_ifalias)
		return -ENOMEM;
	dev->ifalias = new_ifalias;

	strlcpy(dev->ifalias, alias, len+1);
	return len;
}


/**
 *	netdev_features_change - device changes features
 *	@dev: device to cause notification
 *
 *	Called to indicate a device has changed features.
 */
void netdev_features_change(struct net_device *dev)
{
	call_netdevice_notifiers(NETDEV_FEAT_CHANGE, dev);
}
EXPORT_SYMBOL(netdev_features_change);

/**
 *	netdev_state_change - device changes state
 *	@dev: device to cause notification
 *
 *	Called to indicate a device has changed state. This function calls
 *	the notifier chains for netdev_chain and sends a NEWLINK message
 *	to the routing socket.
 */
void netdev_state_change(struct net_device *dev)
{
	if (dev->flags & IFF_UP) {
		call_netdevice_notifiers(NETDEV_CHANGE, dev);
		rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
	}
}
EXPORT_SYMBOL(netdev_state_change);

/**
 * 	netdev_notify_peers - notify network peers about existence of @dev
 * 	@dev: network device
 *
 * Generate traffic such that interested network peers are aware of
 * @dev, such as by generating a gratuitous ARP. This may be used when
 * a device wants to inform the rest of the network about some sort of
 * reconfiguration such as a failover event or virtual machine
 * migration.
 */
void netdev_notify_peers(struct net_device *dev)
{
	rtnl_lock();
	call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
	rtnl_unlock();
}
EXPORT_SYMBOL(netdev_notify_peers);

static int __dev_open(struct net_device *dev)
{
	const struct net_device_ops *ops = dev->netdev_ops;
	int ret;

	ASSERT_RTNL();

	if (!netif_device_present(dev))
		return -ENODEV;

	/* Block netpoll from trying to do any rx path servicing.
	 * If we don't do this there is a chance ndo_poll_controller
	 * or ndo_poll may be running while we open the device
	 */
	ret = netpoll_rx_disable(dev);
	if (ret)
		return ret;

	ret = call_netdevice_notifiers(NETDEV_PRE_UP, dev);
	ret = notifier_to_errno(ret);
	if (ret)
		return ret;

	set_bit(__LINK_STATE_START, &dev->state);

	if (ops->ndo_validate_addr)
		ret = ops->ndo_validate_addr(dev);

	if (!ret && ops->ndo_open)
		ret = ops->ndo_open(dev);

	netpoll_rx_enable(dev);

	if (ret)
		clear_bit(__LINK_STATE_START, &dev->state);
	else {
		dev->flags |= IFF_UP;
		net_dmaengine_get();
		dev_set_rx_mode(dev);
		dev_activate(dev);
		add_device_randomness(dev->dev_addr, dev->addr_len);
	}

	return ret;
}

/**
 *	dev_open	- prepare an interface for use.
 *	@dev:	device to open
 *
 *	Takes a device from down to up state. The device's private open
 *	function is invoked and then the multicast lists are loaded. Finally
 *	the device is moved into the up state and a %NETDEV_UP message is
 *	sent to the netdev notifier chain.
 *
 *	Calling this function on an active interface is a nop. On a failure
 *	a negative errno code is returned.
 */
int dev_open(struct net_device *dev)
{
	int ret;

	if (dev->flags & IFF_UP)
		return 0;

	ret = __dev_open(dev);
	if (ret < 0)
		return ret;

	rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);
	call_netdevice_notifiers(NETDEV_UP, dev);

	return ret;
}
EXPORT_SYMBOL(dev_open);

static int __dev_close_many(struct list_head *head)
{
	struct net_device *dev;

	ASSERT_RTNL();
	might_sleep();

	list_for_each_entry(dev, head, unreg_list) {
		call_netdevice_notifiers(NETDEV_GOING_DOWN, dev);

		clear_bit(__LINK_STATE_START, &dev->state);

		/* Synchronize to scheduled poll. We cannot touch poll list, it
		 * can be even on different cpu. So just clear netif_running().
		 *
		 * dev->stop() will invoke napi_disable() on all of it's
		 * napi_struct instances on this device.
		 */
		smp_mb__after_clear_bit(); /* Commit netif_running(). */
	}

	dev_deactivate_many(head);

	list_for_each_entry(dev, head, unreg_list) {
		const struct net_device_ops *ops = dev->netdev_ops;

		/*
		 *	Call the device specific close. This cannot fail.
		 *	Only if device is UP
		 *
		 *	We allow it to be called even after a DETACH hot-plug
		 *	event.
		 */
		if (ops->ndo_stop)
			ops->ndo_stop(dev);

		dev->flags &= ~IFF_UP;
		net_dmaengine_put();
	}

	return 0;
}

static int __dev_close(struct net_device *dev)
{
	int retval;
	LIST_HEAD(single);

	/* Temporarily disable netpoll until the interface is down */
	retval = netpoll_rx_disable(dev);
	if (retval)
		return retval;

	list_add(&dev->unreg_list, &single);
	retval = __dev_close_many(&single);
	list_del(&single);

	netpoll_rx_enable(dev);
	return retval;
}

static int dev_close_many(struct list_head *head)
{
	struct net_device *dev, *tmp;
	LIST_HEAD(tmp_list);

	list_for_each_entry_safe(dev, tmp, head, unreg_list)
		if (!(dev->flags & IFF_UP))
			list_move(&dev->unreg_list, &tmp_list);

	__dev_close_many(head);

	list_for_each_entry(dev, head, unreg_list) {
		rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);
		call_netdevice_notifiers(NETDEV_DOWN, dev);
	}

	/* rollback_registered_many needs the complete original list */
	list_splice(&tmp_list, head);
	return 0;
}

/**
 *	dev_close - shutdown an interface.
 *	@dev: device to shutdown
 *
 *	This function moves an active device into down state. A
 *	%NETDEV_GOING_DOWN is sent to the netdev notifier chain. The device
 *	is then deactivated and finally a %NETDEV_DOWN is sent to the notifier
 *	chain.
 */
int dev_close(struct net_device *dev)
{
	int ret = 0;
	if (dev->flags & IFF_UP) {
		LIST_HEAD(single);

		/* Block netpoll rx while the interface is going down */
		ret = netpoll_rx_disable(dev);
		if (ret)
			return ret;

		list_add(&dev->unreg_list, &single);
		dev_close_many(&single);
		list_del(&single);

		netpoll_rx_enable(dev);
	}
	return ret;
}
EXPORT_SYMBOL(dev_close);


/**
 *	dev_disable_lro - disable Large Receive Offload on a device
 *	@dev: device
 *
 *	Disable Large Receive Offload (LRO) on a net device.  Must be
 *	called under RTNL.  This is needed if received packets may be
 *	forwarded to another interface.
 */
void dev_disable_lro(struct net_device *dev)
{
	/*
	 * If we're trying to disable lro on a vlan device
	 * use the underlying physical device instead
	 */
	if (is_vlan_dev(dev))
		dev = vlan_dev_real_dev(dev);

	dev->wanted_features &= ~NETIF_F_LRO;
	netdev_update_features(dev);

	if (unlikely(dev->features & NETIF_F_LRO))
		netdev_WARN(dev, "failed to disable LRO!\n");
}
EXPORT_SYMBOL(dev_disable_lro);


static int dev_boot_phase = 1;

/**
 *	register_netdevice_notifier - register a network notifier block
 *	@nb: notifier
 *
 *	Register a notifier to be called when network device events occur.
 *	The notifier passed is linked into the kernel structures and must
 *	not be reused until it has been unregistered. A negative errno code
 *	is returned on a failure.
 *
 * 	When registered all registration and up events are replayed
 *	to the new notifier to allow device to have a race free
 *	view of the network device list.
 */

int register_netdevice_notifier(struct notifier_block *nb)
{
	struct net_device *dev;
	struct net_device *last;
	struct net *net;
	int err;

	rtnl_lock();
	err = raw_notifier_chain_register(&netdev_chain, nb);
	if (err)
		goto unlock;
	if (dev_boot_phase)
		goto unlock;
	for_each_net(net) {
		for_each_netdev(net, dev) {
			err = nb->notifier_call(nb, NETDEV_REGISTER, dev);
			err = notifier_to_errno(err);
			if (err)
				goto rollback;

			if (!(dev->flags & IFF_UP))
				continue;

			nb->notifier_call(nb, NETDEV_UP, dev);
		}
	}

unlock:
	rtnl_unlock();
	return err;

rollback:
	last = dev;
	for_each_net(net) {
		for_each_netdev(net, dev) {
			if (dev == last)
				goto outroll;

			if (dev->flags & IFF_UP) {
				nb->notifier_call(nb, NETDEV_GOING_DOWN, dev);
				nb->notifier_call(nb, NETDEV_DOWN, dev);
			}
			nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
		}
	}

outroll:
	raw_notifier_chain_unregister(&netdev_chain, nb);
	goto unlock;
}
EXPORT_SYMBOL(register_netdevice_notifier);

/**
 *	unregister_netdevice_notifier - unregister a network notifier block
 *	@nb: notifier
 *
 *	Unregister a notifier previously registered by
 *	register_netdevice_notifier(). The notifier is unlinked into the
 *	kernel structures and may then be reused. A negative errno code
 *	is returned on a failure.
 *
 * 	After unregistering unregister and down device events are synthesized
 *	for all devices on the device list to the removed notifier to remove
 *	the need for special case cleanup code.
 */

int unregister_netdevice_notifier(struct notifier_block *nb)
{
	struct net_device *dev;
	struct net *net;
	int err;

	rtnl_lock();
	err = raw_notifier_chain_unregister(&netdev_chain, nb);
	if (err)
		goto unlock;

	for_each_net(net) {
		for_each_netdev(net, dev) {
			if (dev->flags & IFF_UP) {
				nb->notifier_call(nb, NETDEV_GOING_DOWN, dev);
				nb->notifier_call(nb, NETDEV_DOWN, dev);
			}
			nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
		}
	}
unlock:
	rtnl_unlock();
	return err;
}
EXPORT_SYMBOL(unregister_netdevice_notifier);

/**
 *	call_netdevice_notifiers - call all network notifier blocks
 *      @val: value passed unmodified to notifier function
 *      @dev: net_device pointer passed unmodified to notifier function
 *
 *	Call all network notifier blocks.  Parameters and return value
 *	are as for raw_notifier_call_chain().
 */

int call_netdevice_notifiers(unsigned long val, struct net_device *dev)
{
	ASSERT_RTNL();
	return raw_notifier_call_chain(&netdev_chain, val, dev);
}
EXPORT_SYMBOL(call_netdevice_notifiers);

static struct static_key netstamp_needed __read_mostly;
#ifdef HAVE_JUMP_LABEL
/* We are not allowed to call static_key_slow_dec() from irq context
 * If net_disable_timestamp() is called from irq context, defer the
 * static_key_slow_dec() calls.
 */
static atomic_t netstamp_needed_deferred;
#endif

void net_enable_timestamp(void)
{
#ifdef HAVE_JUMP_LABEL
	int deferred = atomic_xchg(&netstamp_needed_deferred, 0);

	if (deferred) {
		while (--deferred)
			static_key_slow_dec(&netstamp_needed);
		return;
	}
#endif
	WARN_ON(in_interrupt());
	static_key_slow_inc(&netstamp_needed);
}
EXPORT_SYMBOL(net_enable_timestamp);

void net_disable_timestamp(void)
{
#ifdef HAVE_JUMP_LABEL
	if (in_interrupt()) {
		atomic_inc(&netstamp_needed_deferred);
		return;
	}
#endif
	static_key_slow_dec(&netstamp_needed);
}
EXPORT_SYMBOL(net_disable_timestamp);

static inline void net_timestamp_set(struct sk_buff *skb)
{
	skb->tstamp.tv64 = 0;
	if (static_key_false(&netstamp_needed))
		__net_timestamp(skb);
}

#define net_timestamp_check(COND, SKB)			\
	if (static_key_false(&netstamp_needed)) {		\
		if ((COND) && !(SKB)->tstamp.tv64)	\
			__net_timestamp(SKB);		\
	}						\

static inline bool is_skb_forwardable(struct net_device *dev,
				      struct sk_buff *skb)
{
	unsigned int len;

	if (!(dev->flags & IFF_UP))
		return false;

	len = dev->mtu + dev->hard_header_len + VLAN_HLEN;
	if (skb->len <= len)
		return true;

	/* if TSO is enabled, we don't care about the length as the packet
	 * could be forwarded without being segmented before
	 */
	if (skb_is_gso(skb))
		return true;

	return false;
}

/**
 * dev_forward_skb - loopback an skb to another netif
 *
 * @dev: destination network device
 * @skb: buffer to forward
 *
 * return values:
 *	NET_RX_SUCCESS	(no congestion)
 *	NET_RX_DROP     (packet was dropped, but freed)
 *
 * dev_forward_skb can be used for injecting an skb from the
 * start_xmit function of one device into the receive queue
 * of another device.
 *
 * The receiving device may be in another namespace, so
 * we have to clear all information in the skb that could
 * impact namespace isolation.
 */
int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
{
	if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
		if (skb_copy_ubufs(skb, GFP_ATOMIC)) {
			atomic_long_inc(&dev->rx_dropped);
			kfree_skb(skb);
			return NET_RX_DROP;
		}
	}

	skb_orphan(skb);
	nf_reset(skb);

	if (unlikely(!is_skb_forwardable(dev, skb))) {
		atomic_long_inc(&dev->rx_dropped);
		kfree_skb(skb);
		return NET_RX_DROP;
	}
	skb->skb_iif = 0;
	skb->dev = dev;
	skb_dst_drop(skb);
	skb->tstamp.tv64 = 0;
	skb->pkt_type = PACKET_HOST;
	skb->protocol = eth_type_trans(skb, dev);
	skb->mark = 0;
	secpath_reset(skb);
	nf_reset(skb);
	return netif_rx(skb);
}
EXPORT_SYMBOL_GPL(dev_forward_skb);

static inline int deliver_skb(struct sk_buff *skb,
			      struct packet_type *pt_prev,
			      struct net_device *orig_dev)
{
	if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
		return -ENOMEM;
	atomic_inc(&skb->users);
	return pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
}

static inline bool skb_loop_sk(struct packet_type *ptype, struct sk_buff *skb)
{
	if (!ptype->af_packet_priv || !skb->sk)
		return false;

	if (ptype->id_match)
		return ptype->id_match(ptype, skb->sk);
	else if ((struct sock *)ptype->af_packet_priv == skb->sk)
		return true;

	return false;
}

/*
 *	Support routine. Sends outgoing frames to any network
 *	taps currently in use.
 */

static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
{
	struct packet_type *ptype;
	struct sk_buff *skb2 = NULL;
	struct packet_type *pt_prev = NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(ptype, &ptype_all, list) {
		/* Never send packets back to the socket
		 * they originated from - MvS (miquels@drinkel.ow.org)
		 */
		if ((ptype->dev == dev || !ptype->dev) &&
		    (!skb_loop_sk(ptype, skb))) {
			if (pt_prev) {
				deliver_skb(skb2, pt_prev, skb->dev);
				pt_prev = ptype;
				continue;
			}

			skb2 = skb_clone(skb, GFP_ATOMIC);
			if (!skb2)
				break;

			net_timestamp_set(skb2);

			/* skb->nh should be correctly
			   set by sender, so that the second statement is
			   just protection against buggy protocols.
			 */
			skb_reset_mac_header(skb2);

			if (skb_network_header(skb2) < skb2->data ||
			    skb2->network_header > skb2->tail) {
				net_crit_ratelimited("protocol %04x is buggy, dev %s\n",
						     ntohs(skb2->protocol),
						     dev->name);
				skb_reset_network_header(skb2);
			}

			skb2->transport_header = skb2->network_header;
			skb2->pkt_type = PACKET_OUTGOING;
			pt_prev = ptype;
		}
	}
	if (pt_prev)
		pt_prev->func(skb2, skb->dev, pt_prev, skb->dev);
	rcu_read_unlock();
}

/**
 * netif_setup_tc - Handle tc mappings on real_num_tx_queues change
 * @dev: Network device
 * @txq: number of queues available
 *
 * If real_num_tx_queues is changed the tc mappings may no longer be
 * valid. To resolve this verify the tc mapping remains valid and if
 * not NULL the mapping. With no priorities mapping to this
 * offset/count pair it will no longer be used. In the worst case TC0
 * is invalid nothing can be done so disable priority mappings. If is
 * expected that drivers will fix this mapping if they can before
 * calling netif_set_real_num_tx_queues.
 */
static void netif_setup_tc(struct net_device *dev, unsigned int txq)
{
	int i;
	struct netdev_tc_txq *tc = &dev->tc_to_txq[0];

	/* If TC0 is invalidated disable TC mapping */
	if (tc->offset + tc->count > txq) {
		pr_warn("Number of in use tx queues changed invalidating tc mappings. Priority traffic classification disabled!\n");
		dev->num_tc = 0;
		return;
	}

	/* Invalidated prio to tc mappings set to TC0 */
	for (i = 1; i < TC_BITMASK + 1; i++) {
		int q = netdev_get_prio_tc_map(dev, i);

		tc = &dev->tc_to_txq[q];
		if (tc->offset + tc->count > txq) {
			pr_warn("Number of in use tx queues changed. Priority %i to tc mapping %i is no longer valid. Setting map to 0\n",
				i, q);
			netdev_set_prio_tc_map(dev, i, 0);
		}
	}
}

#ifdef CONFIG_XPS
static DEFINE_MUTEX(xps_map_mutex);
#define xmap_dereference(P)		\
	rcu_dereference_protected((P), lockdep_is_held(&xps_map_mutex))

static struct xps_map *remove_xps_queue(struct xps_dev_maps *dev_maps,
					int cpu, u16 index)
{
	struct xps_map *map = NULL;
	int pos;

	if (dev_maps)
		map = xmap_dereference(dev_maps->cpu_map[cpu]);

	for (pos = 0; map && pos < map->len; pos++) {
		if (map->queues[pos] == index) {
			if (map->len > 1) {
				map->queues[pos] = map->queues[--map->len];
			} else {
				RCU_INIT_POINTER(dev_maps->cpu_map[cpu], NULL);
				kfree_rcu(map, rcu);
				map = NULL;
			}
			break;
		}
	}

	return map;
}

static void netif_reset_xps_queues_gt(struct net_device *dev, u16 index)
{
	struct xps_dev_maps *dev_maps;
	int cpu, i;
	bool active = false;

	mutex_lock(&xps_map_mutex);
	dev_maps = xmap_dereference(dev->xps_maps);

	if (!dev_maps)
		goto out_no_maps;

	for_each_possible_cpu(cpu) {
		for (i = index; i < dev->num_tx_queues; i++) {
			if (!remove_xps_queue(dev_maps, cpu, i))
				break;
		}
		if (i == dev->num_tx_queues)
			active = true;
	}

	if (!active) {
		RCU_INIT_POINTER(dev->xps_maps, NULL);
		kfree_rcu(dev_maps, rcu);
	}

	for (i = index; i < dev->num_tx_queues; i++)
		netdev_queue_numa_node_write(netdev_get_tx_queue(dev, i),
					     NUMA_NO_NODE);

out_no_maps:
	mutex_unlock(&xps_map_mutex);
}

static struct xps_map *expand_xps_map(struct xps_map *map,
				      int cpu, u16 index)
{
	struct xps_map *new_map;
	int alloc_len = XPS_MIN_MAP_ALLOC;
	int i, pos;

	for (pos = 0; map && pos < map->len; pos++) {
		if (map->queues[pos] != index)
			continue;
		return map;
	}

	/* Need to add queue to this CPU's existing map */
	if (map) {
		if (pos < map->alloc_len)
			return map;

		alloc_len = map->alloc_len * 2;
	}

	/* Need to allocate new map to store queue on this CPU's map */
	new_map = kzalloc_node(XPS_MAP_SIZE(alloc_len), GFP_KERNEL,
			       cpu_to_node(cpu));
	if (!new_map)
		return NULL;

	for (i = 0; i < pos; i++)
		new_map->queues[i] = map->queues[i];
	new_map->alloc_len = alloc_len;
	new_map->len = pos;

	return new_map;
}

int netif_set_xps_queue(struct net_device *dev, struct cpumask *mask, u16 index)
{
	struct xps_dev_maps *dev_maps, *new_dev_maps = NULL;
	struct xps_map *map, *new_map;
	int maps_sz = max_t(unsigned int, XPS_DEV_MAPS_SIZE, L1_CACHE_BYTES);
	int cpu, numa_node_id = -2;
	bool active = false;

	mutex_lock(&xps_map_mutex);

	dev_maps = xmap_dereference(dev->xps_maps);

	/* allocate memory for queue storage */
	for_each_online_cpu(cpu) {
		if (!cpumask_test_cpu(cpu, mask))
			continue;

		if (!new_dev_maps)
			new_dev_maps = kzalloc(maps_sz, GFP_KERNEL);
		if (!new_dev_maps) {
			mutex_unlock(&xps_map_mutex);
			return -ENOMEM;
		}

		map = dev_maps ? xmap_dereference(dev_maps->cpu_map[cpu]) :
				 NULL;

		map = expand_xps_map(map, cpu, index);
		if (!map)
			goto error;

		RCU_INIT_POINTER(new_dev_maps->cpu_map[cpu], map);
	}

	if (!new_dev_maps)
		goto out_no_new_maps;

	for_each_possible_cpu(cpu) {
		if (cpumask_test_cpu(cpu, mask) && cpu_online(cpu)) {
			/* add queue to CPU maps */
			int pos = 0;

			map = xmap_dereference(new_dev_maps->cpu_map[cpu]);
			while ((pos < map->len) && (map->queues[pos] != index))
				pos++;

			if (pos == map->len)
				map->queues[map->len++] = index;
#ifdef CONFIG_NUMA
			if (numa_node_id == -2)
				numa_node_id = cpu_to_node(cpu);
			else if (numa_node_id != cpu_to_node(cpu))
				numa_node_id = -1;
#endif
		} else if (dev_maps) {
			/* fill in the new device map from the old device map */
			map = xmap_dereference(dev_maps->cpu_map[cpu]);
			RCU_INIT_POINTER(new_dev_maps->cpu_map[cpu], map);
		}

	}

	rcu_assign_pointer(dev->xps_maps, new_dev_maps);

	/* Cleanup old maps */
	if (dev_maps) {
		for_each_possible_cpu(cpu) {
			new_map = xmap_dereference(new_dev_maps->cpu_map[cpu]);
			map = xmap_dereference(dev_maps->cpu_map[cpu]);
			if (map && map != new_map)
				kfree_rcu(map, rcu);
		}

		kfree_rcu(dev_maps, rcu);
	}

	dev_maps = new_dev_maps;
	active = true;

out_no_new_maps:
	/* update Tx queue numa node */
	netdev_queue_numa_node_write(netdev_get_tx_queue(dev, index),
				     (numa_node_id >= 0) ? numa_node_id :
				     NUMA_NO_NODE);

	if (!dev_maps)
		goto out_no_maps;

	/* removes queue from unused CPUs */
	for_each_possible_cpu(cpu) {
		if (cpumask_test_cpu(cpu, mask) && cpu_online(cpu))
			continue;

		if (remove_xps_queue(dev_maps, cpu, index))
			active = true;
	}

	/* free map if not active */
	if (!active) {
		RCU_INIT_POINTER(dev->xps_maps, NULL);
		kfree_rcu(dev_maps, rcu);
	}

out_no_maps:
	mutex_unlock(&xps_map_mutex);

	return 0;
error:
	/* remove any maps that we added */
	for_each_possible_cpu(cpu) {
		new_map = xmap_dereference(new_dev_maps->cpu_map[cpu]);
		map = dev_maps ? xmap_dereference(dev_maps->cpu_map[cpu]) :
				 NULL;
		if (new_map && new_map != map)
			kfree(new_map);
	}

	mutex_unlock(&xps_map_mutex);

	kfree(new_dev_maps);
	return -ENOMEM;
}
EXPORT_SYMBOL(netif_set_xps_queue);

#endif
/*
 * Routine to help set real_num_tx_queues. To avoid skbs mapped to queues
 * greater then real_num_tx_queues stale skbs on the qdisc must be flushed.
 */
int netif_set_real_num_tx_queues(struct net_device *dev, unsigned int txq)
{
	int rc;

	if (txq < 1 || txq > dev->num_tx_queues)
		return -EINVAL;