C++ rtnl_dereference函数代码示例

/* holding rtnl */
static void vrf_rtable_release(struct net_device *dev, struct net_vrf *vrf)
{
	struct rtable *rth = rtnl_dereference(vrf->rth);
	struct rtable *rth_local = rtnl_dereference(vrf->rth_local);
	struct net *net = dev_net(dev);
	struct dst_entry *dst;

	RCU_INIT_POINTER(vrf->rth, NULL);
	RCU_INIT_POINTER(vrf->rth_local, NULL);
	synchronize_rcu();

	/* move dev in dst's to loopback so this VRF device can be deleted
	 * - based on dst_ifdown
	 */
	if (rth) {
		dst = &rth->dst;
		dev_put(dst->dev);
		dst->dev = net->loopback_dev;
		dev_hold(dst->dev);
		dst_release(dst);
	}

	if (rth_local) {
		dst = &rth_local->dst;
		dev_put(dst->dev);
		dst->dev = net->loopback_dev;
		dev_hold(dst->dev);
		dst_release(dst);
	}
}

void bnxt_ulp_irq_restart(struct bnxt *bp, int err)
{
	struct bnxt_en_dev *edev = bp->edev;
	struct bnxt_ulp_ops *ops;

	if (!edev || !(edev->flags & BNXT_EN_FLAG_MSIX_REQUESTED))
		return;

	if (bnxt_ulp_registered(bp->edev, BNXT_ROCE_ULP)) {
		struct bnxt_ulp *ulp = &edev->ulp_tbl[BNXT_ROCE_ULP];
		struct bnxt_msix_entry *ent = NULL;

		if (!ulp->msix_requested)
			return;

		ops = rtnl_dereference(ulp->ulp_ops);
		if (!ops || !ops->ulp_irq_restart)
			return;

		if (!err) {
			ent = kcalloc(ulp->msix_requested, sizeof(*ent),
				      GFP_KERNEL);
			if (!ent)
				return;
			bnxt_fill_msix_vecs(bp, ent);
		}
		ops->ulp_irq_restart(ulp->handle, ent);
		kfree(ent);
	}
}

void qdisc_destroy(struct Qdisc *qdisc)
{
	const struct Qdisc_ops  *ops = qdisc->ops;

	if (qdisc->flags & TCQ_F_BUILTIN ||
	    !atomic_dec_and_test(&qdisc->refcnt))
		return;

#ifdef CONFIG_NET_SCHED
	qdisc_list_del(qdisc);

	qdisc_put_stab(rtnl_dereference(qdisc->stab));
#endif
	gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
	if (ops->reset)
		ops->reset(qdisc);
	if (ops->destroy)
		ops->destroy(qdisc);

	module_put(ops->owner);
	dev_put(qdisc_dev(qdisc));

	kfree_skb_list(qdisc->gso_skb);
	/*
	 * gen_estimator est_timer() might access qdisc->q.lock,
	 * wait a RCU grace period before freeing qdisc.
	 */
	call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
}

/* Must be protected by RTNL */
int br_vlan_add(struct net_bridge *br, u16 vid, u16 flags)
{
	struct net_port_vlans *pv = NULL;
	int err;

	ASSERT_RTNL();

	pv = rtnl_dereference(br->vlan_info);
	if (pv)
		return __vlan_add(pv, vid, flags);

	/* Create port vlan infomration
	 */
	pv = kzalloc(sizeof(*pv), GFP_KERNEL);
	if (!pv)
		return -ENOMEM;

	pv->parent.br = br;
	err = __vlan_add(pv, vid, flags);
	if (err)
		goto out;

	rcu_assign_pointer(br->vlan_info, pv);
	return 0;
out:
	kfree(pv);
	return err;
}

/**
 * tipc_l2_device_event - handle device events from network device
 * @nb: the context of the notification
 * @evt: the type of event
 * @ptr: the net device that the event was on
 *
 * This function is called by the Ethernet driver in case of link
 * change event.
 */
static int tipc_l2_device_event(struct notifier_block *nb, unsigned long evt,
				void *ptr)
{
	struct tipc_bearer *b_ptr;
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

	if (!net_eq(dev_net(dev), &init_net))
		return NOTIFY_DONE;

	b_ptr = rtnl_dereference(dev->tipc_ptr);
	if (!b_ptr)
		return NOTIFY_DONE;

	b_ptr->mtu = dev->mtu;

	switch (evt) {
	case NETDEV_CHANGE:
		if (netif_carrier_ok(dev))
			break;
	case NETDEV_DOWN:
	case NETDEV_CHANGEMTU:
		tipc_reset_bearer(b_ptr);
		break;
	case NETDEV_CHANGEADDR:
		b_ptr->media->raw2addr(b_ptr, &b_ptr->addr,
				       (char *)dev->dev_addr);
		tipc_reset_bearer(b_ptr);
		break;
	case NETDEV_UNREGISTER:
	case NETDEV_CHANGENAME:
		bearer_disable(b_ptr, false);
		break;
	}
	return NOTIFY_OK;
}

static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir,
			   const u8 *key, const u8 hfunc)
{
	struct net_device_context *ndc = netdev_priv(dev);
	struct netvsc_device *ndev = rtnl_dereference(ndc->nvdev);
	struct rndis_device *rndis_dev;
	int i;

	if (!ndev)
		return -ENODEV;

	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
		return -EOPNOTSUPP;

	rndis_dev = ndev->extension;
	if (indir) {
		for (i = 0; i < ITAB_NUM; i++)
			if (indir[i] >= VRSS_CHANNEL_MAX)
				return -EINVAL;

		for (i = 0; i < ITAB_NUM; i++)
			rndis_dev->ind_table[i] = indir[i];
	}

	if (!key) {
		if (!indir)
			return 0;

		key = rndis_dev->rss_key;
	}

	return rndis_filter_set_rss_param(rndis_dev, key, ndev->num_chn);
}

int tipc_nl_bearer_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
	int err;
	int i = cb->args[0];
	struct tipc_bearer *bearer;
	struct tipc_nl_msg msg;
	struct net *net = sock_net(skb->sk);
	struct tipc_net *tn = net_generic(net, tipc_net_id);

	if (i == MAX_BEARERS)
		return 0;

	msg.skb = skb;
	msg.portid = NETLINK_CB(cb->skb).portid;
	msg.seq = cb->nlh->nlmsg_seq;

	rtnl_lock();
	for (i = 0; i < MAX_BEARERS; i++) {
		bearer = rtnl_dereference(tn->bearer_list[i]);
		if (!bearer)
			continue;

		err = __tipc_nl_add_bearer(&msg, bearer);
		if (err)
			break;
	}
	rtnl_unlock();

	cb->args[0] = i;
	return skb->len;
}

static int patch_set_options(struct vport *vport, struct nlattr *options)
{
	struct patch_vport *patch_vport = patch_vport_priv(vport);
	struct patch_config *patchconf;
	int err;

	patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
			  sizeof(struct patch_config), GFP_KERNEL);
	if (!patchconf) {
		err = -ENOMEM;
		goto error;
	}

	err = patch_set_config(vport, options, patchconf);
	if (err)
		goto error_free;

	assign_config_rcu(vport, patchconf);

	hlist_del(&patch_vport->hash_node);

	rcu_assign_pointer(patch_vport->peer,
		ovs_vport_locate(ovs_dp_get_net(vport->dp), patchconf->peer_name));

	hlist_add_head(&patch_vport->hash_node,
		       hash_bucket(ovs_dp_get_net(vport->dp), patchconf->peer_name));

	return 0;
error_free:
	kfree(patchconf);
error:
	return err;
}

static void netvsc_set_multicast_list(struct net_device *net)
{
	struct net_device_context *net_device_ctx = netdev_priv(net);
	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);

	rndis_filter_update(nvdev);
}

void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
{
	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
	struct net_device *real_dev = vlan->real_dev;
	struct vlan_info *vlan_info;
	struct vlan_group *grp;
	u16 vlan_id = vlan->vlan_id;

	ASSERT_RTNL();

	vlan_info = rtnl_dereference(real_dev->vlan_info);
	BUG_ON(!vlan_info);

	grp = &vlan_info->grp;

	if (vlan_id)
		vlan_vid_del(real_dev, vlan_id);

	grp->nr_vlan_devs--;

	if (vlan->flags & VLAN_FLAG_GVRP)
		vlan_gvrp_request_leave(dev);

	vlan_group_set_device(grp, vlan_id, NULL);
	unregister_netdevice_queue(dev, head);

	if (grp->nr_vlan_devs == 0)
		vlan_gvrp_uninit_applicant(real_dev);

	
	dev_put(real_dev);
}

static struct net *vxcan_get_link_net(const struct net_device *dev)
{
	struct vxcan_priv *priv = netdev_priv(dev);
	struct net_device *peer = rtnl_dereference(priv->peer);

	return peer ? dev_net(peer) : dev_net(dev);
}

/* Must be protected by RTNL */
int nbp_vlan_add(struct net_bridge_port *port, u16 vid, u16 flags)
{
	struct net_port_vlans *pv = NULL;
	int err;

	ASSERT_RTNL();

	pv = rtnl_dereference(port->vlan_info);
	if (pv)
		return __vlan_add(pv, vid, flags);

	/* Create port vlan infomration
	 */
	pv = kzalloc(sizeof(*pv), GFP_KERNEL);
	if (!pv) {
		err = -ENOMEM;
		goto clean_up;
	}

	pv->port_idx = port->port_no;
	pv->parent.port = port;
	err = __vlan_add(pv, vid, flags);
	if (err)
		goto clean_up;

	rcu_assign_pointer(port->vlan_info, pv);
	return 0;

clean_up:
	kfree(pv);
	return err;
}

int register_vlan_dev(struct net_device *dev)
{
	struct vlan_dev_info *vlan = vlan_dev_info(dev);
	struct net_device *real_dev = vlan->real_dev;
	const struct net_device_ops *ops = real_dev->netdev_ops;
	u16 vlan_id = vlan->vlan_id;
	struct vlan_group *grp, *ngrp = NULL;
	int err;

	grp = rtnl_dereference(real_dev->vlgrp);
	if (!grp) {
		ngrp = grp = vlan_group_alloc(real_dev);
		if (!grp)
			return -ENOBUFS;
		err = vlan_gvrp_init_applicant(real_dev);
		if (err < 0)
			goto out_free_group;
	}

	err = vlan_group_prealloc_vid(grp, vlan_id);
	if (err < 0)
		goto out_uninit_applicant;

	err = register_netdevice(dev);
	if (err < 0)
		goto out_uninit_applicant;

	/* Account for reference in struct vlan_dev_info */
	dev_hold(real_dev);

	netif_stacked_transfer_operstate(real_dev, dev);
	linkwatch_fire_event(dev); /* _MUST_ call rfc2863_policy() */

	/* So, got the sucker initialized, now lets place
	 * it into our local structure.
	 */
	vlan_group_set_device(grp, vlan_id, dev);
	grp->nr_vlans++;

	if (ngrp) {
		if (ops->ndo_vlan_rx_register)
			ops->ndo_vlan_rx_register(real_dev, ngrp);
		rcu_assign_pointer(real_dev->vlgrp, ngrp);
	}
	if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
		ops->ndo_vlan_rx_add_vid(real_dev, vlan_id);

	return 0;

out_uninit_applicant:
	if (ngrp)
		vlan_gvrp_uninit_applicant(real_dev);
out_free_group:
	if (ngrp) {
		/* Free the group, after all cpu's are done. */
		call_rcu(&ngrp->rcu, vlan_rcu_free);
	}
	return err;
}

static void veth_get_ethtool_stats(struct net_device *dev,
		struct ethtool_stats *stats, u64 *data)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer = rtnl_dereference(priv->peer);

	data[0] = peer ? peer->ifindex : 0;
}

static void tcf_sample_cleanup(struct tc_action *a)
{
	struct tcf_sample *s = to_sample(a);
	struct psample_group *psample_group;

	psample_group = rtnl_dereference(s->psample_group);
	RCU_INIT_POINTER(s->psample_group, NULL);
	psample_group_put(psample_group);
}