Initial import

1 files changed, 852 insertions, 0 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
new file mode 100644
index 000000000..c126a878c
--- /dev/null
+++ b/net/core/netpoll.c
@@ -0,0 +1,852 @@
+/*
+ * Common framework for low-level network console, dump, and debugger code
+ *
+ * Sep 8 2003  Matt Mackall <mpm@selenic.com>
+ *
+ * based on the netconsole code from:
+ *
+ * Copyright (C) 2001  Ingo Molnar <mingo@redhat.com>
+ * Copyright (C) 2002  Red Hat, Inc.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/string.h>
+#include <linux/if_arp.h>
+#include <linux/inetdevice.h>
+#include <linux/inet.h>
+#include <linux/interrupt.h>
+#include <linux/netpoll.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/rcupdate.h>
+#include <linux/workqueue.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/if_vlan.h>
+#include <net/tcp.h>
+#include <net/udp.h>
+#include <net/addrconf.h>
+#include <net/ndisc.h>
+#include <net/ip6_checksum.h>
+#include <asm/unaligned.h>
+#include <trace/events/napi.h>
+
+/*
+ * We maintain a small pool of fully-sized skbs, to make sure the
+ * message gets out even in extreme OOM situations.
+ */
+
+#define MAX_UDP_CHUNK 1460
+#define MAX_SKBS 32
+
+static struct sk_buff_head skb_pool;
+
+DEFINE_STATIC_SRCU(netpoll_srcu);
+
+#define USEC_PER_POLL	50
+
+#define MAX_SKB_SIZE							\
+	(sizeof(struct ethhdr) +					\
+	 sizeof(struct iphdr) +						\
+	 sizeof(struct udphdr) +					\
+	 MAX_UDP_CHUNK)
+
+static void zap_completion_queue(void);
+static void netpoll_async_cleanup(struct work_struct *work);
+
+static unsigned int carrier_timeout = 4;
+module_param(carrier_timeout, uint, 0644);
+
+#define np_info(np, fmt, ...)				\
+	pr_info("%s: " fmt, np->name, ##__VA_ARGS__)
+#define np_err(np, fmt, ...)				\
+	pr_err("%s: " fmt, np->name, ##__VA_ARGS__)
+#define np_notice(np, fmt, ...)				\
+	pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
+
+static int netpoll_start_xmit(struct sk_buff *skb, struct net_device *dev,
+			      struct netdev_queue *txq)
+{
+	int status = NETDEV_TX_OK;
+	netdev_features_t features;
+
+	features = netif_skb_features(skb);
+
+	if (skb_vlan_tag_present(skb) &&
+	    !vlan_hw_offload_capable(features, skb->vlan_proto)) {
+		skb = __vlan_hwaccel_push_inside(skb);
+		if (unlikely(!skb)) {
+			/* This is actually a packet drop, but we
+			 * don't want the code that calls this
+			 * function to try and operate on a NULL skb.
+			 */
+			goto out;
+		}
+	}
+
+	status = netdev_start_xmit(skb, dev, txq, false);
+
+out:
+	return status;
+}
+
+static void queue_process(struct work_struct *work)
+{
+	struct netpoll_info *npinfo =
+		container_of(work, struct netpoll_info, tx_work.work);
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	while ((skb = skb_dequeue(&npinfo->txq))) {
+		struct net_device *dev = skb->dev;
+		struct netdev_queue *txq;
+
+		if (!netif_device_present(dev) || !netif_running(dev)) {
+			kfree_skb(skb);
+			continue;
+		}
+
+		txq = skb_get_tx_queue(dev, skb);
+
+		local_irq_save(flags);
+		HARD_TX_LOCK(dev, txq, smp_processor_id());
+		if (netif_xmit_frozen_or_stopped(txq) ||
+		    netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) {
+			skb_queue_head(&npinfo->txq, skb);
+			HARD_TX_UNLOCK(dev, txq);
+			local_irq_restore(flags);
+
+			schedule_delayed_work(&npinfo->tx_work, HZ/10);
+			return;
+		}
+		HARD_TX_UNLOCK(dev, txq);
+		local_irq_restore(flags);
+	}
+}
+
+/*
+ * Check whether delayed processing was scheduled for our NIC. If so,
+ * we attempt to grab the poll lock and use ->poll() to pump the card.
+ * If this fails, either we've recursed in ->poll() or it's already
+ * running on another CPU.
+ *
+ * Note: we don't mask interrupts with this lock because we're using
+ * trylock here and interrupts are already disabled in the softirq
+ * case. Further, we test the poll_owner to avoid recursion on UP
+ * systems where the lock doesn't exist.
+ */
+static int poll_one_napi(struct napi_struct *napi, int budget)
+{
+	int work;
+
+	/* net_rx_action's ->poll() invocations and our's are
+	 * synchronized by this test which is only made while
+	 * holding the napi->poll_lock.
+	 */
+	if (!test_bit(NAPI_STATE_SCHED, &napi->state))
+		return budget;
+
+	set_bit(NAPI_STATE_NPSVC, &napi->state);
+
+	work = napi->poll(napi, budget);
+	WARN_ONCE(work > budget, "%pF exceeded budget in poll\n", napi->poll);
+	trace_napi_poll(napi);
+
+	clear_bit(NAPI_STATE_NPSVC, &napi->state);
+
+	return budget - work;
+}
+
+static void poll_napi(struct net_device *dev, int budget)
+{
+	struct napi_struct *napi;
+
+	list_for_each_entry(napi, &dev->napi_list, dev_list) {
+		if (napi->poll_owner != smp_processor_id() &&
+		    spin_trylock(&napi->poll_lock)) {
+			budget = poll_one_napi(napi, budget);
+			spin_unlock(&napi->poll_lock);
+		}
+	}
+}
+
+static void netpoll_poll_dev(struct net_device *dev)
+{
+	const struct net_device_ops *ops;
+	struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
+	int budget = 0;
+
+	/* Don't do any rx activity if the dev_lock mutex is held
+	 * the dev_open/close paths use this to block netpoll activity
+	 * while changing device state
+	 */
+	if (down_trylock(&ni->dev_lock))
+		return;
+
+	if (!netif_running(dev)) {
+		up(&ni->dev_lock);
+		return;
+	}
+
+	ops = dev->netdev_ops;
+	if (!ops->ndo_poll_controller) {
+		up(&ni->dev_lock);
+		return;
+	}
+
+	/* Process pending work on NIC */
+	ops->ndo_poll_controller(dev);
+
+	poll_napi(dev, budget);
+
+	up(&ni->dev_lock);
+
+	zap_completion_queue();
+}
+
+void netpoll_poll_disable(struct net_device *dev)
+{
+	struct netpoll_info *ni;
+	int idx;
+	might_sleep();
+	idx = srcu_read_lock(&netpoll_srcu);
+	ni = srcu_dereference(dev->npinfo, &netpoll_srcu);
+	if (ni)
+		down(&ni->dev_lock);
+	srcu_read_unlock(&netpoll_srcu, idx);
+}
+EXPORT_SYMBOL(netpoll_poll_disable);
+
+void netpoll_poll_enable(struct net_device *dev)
+{
+	struct netpoll_info *ni;
+	rcu_read_lock();
+	ni = rcu_dereference(dev->npinfo);
+	if (ni)
+		up(&ni->dev_lock);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(netpoll_poll_enable);
+
+static void refill_skbs(void)
+{
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	spin_lock_irqsave(&skb_pool.lock, flags);
+	while (skb_pool.qlen < MAX_SKBS) {
+		skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
+		if (!skb)
+			break;
+
+		__skb_queue_tail(&skb_pool, skb);
+	}
+	spin_unlock_irqrestore(&skb_pool.lock, flags);
+}
+
+static void zap_completion_queue(void)
+{
+	unsigned long flags;
+	struct softnet_data *sd = &get_cpu_var(softnet_data);
+
+	if (sd->completion_queue) {
+		struct sk_buff *clist;
+
+		local_irq_save(flags);
+		clist = sd->completion_queue;
+		sd->completion_queue = NULL;
+		local_irq_restore(flags);
+
+		while (clist != NULL) {
+			struct sk_buff *skb = clist;
+			clist = clist->next;
+			if (!skb_irq_freeable(skb)) {
+				atomic_inc(&skb->users);
+				dev_kfree_skb_any(skb); /* put this one back */
+			} else {
+				__kfree_skb(skb);
+			}
+		}
+	}
+
+	put_cpu_var(softnet_data);
+}
+
+static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
+{
+	int count = 0;
+	struct sk_buff *skb;
+
+	zap_completion_queue();
+	refill_skbs();
+repeat:
+
+	skb = alloc_skb(len, GFP_ATOMIC);
+	if (!skb)
+		skb = skb_dequeue(&skb_pool);
+
+	if (!skb) {
+		if (++count < 10) {
+			netpoll_poll_dev(np->dev);
+			goto repeat;
+		}
+		return NULL;
+	}
+
+	atomic_set(&skb->users, 1);
+	skb_reserve(skb, reserve);
+	return skb;
+}
+
+static int netpoll_owner_active(struct net_device *dev)
+{
+	struct napi_struct *napi;
+
+	list_for_each_entry(napi, &dev->napi_list, dev_list) {
+		if (napi->poll_owner == smp_processor_id())
+			return 1;
+	}
+	return 0;
+}
+
+/* call with IRQ disabled */
+void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
+			     struct net_device *dev)
+{
+	int status = NETDEV_TX_BUSY;
+	unsigned long tries;
+	/* It is up to the caller to keep npinfo alive. */
+	struct netpoll_info *npinfo;
+
+	WARN_ON_ONCE(!irqs_disabled());
+
+	npinfo = rcu_dereference_bh(np->dev->npinfo);
+	if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
+		dev_kfree_skb_irq(skb);
+		return;
+	}
+
+	/* don't get messages out of order, and no recursion */
+	if (skb_queue_len(&npinfo->txq) == 0 && !netpoll_owner_active(dev)) {
+		struct netdev_queue *txq;
+
+		txq = netdev_pick_tx(dev, skb, NULL);
+
+		/* try until next clock tick */
+		for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
+		     tries > 0; --tries) {
+			if (HARD_TX_TRYLOCK(dev, txq)) {
+				if (!netif_xmit_stopped(txq))
+					status = netpoll_start_xmit(skb, dev, txq);
+
+				HARD_TX_UNLOCK(dev, txq);
+
+				if (status == NETDEV_TX_OK)
+					break;
+
+			}
+
+			/* tickle device maybe there is some cleanup */
+			netpoll_poll_dev(np->dev);
+
+			udelay(USEC_PER_POLL);
+		}
+
+		WARN_ONCE(!irqs_disabled(),
+			"netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
+			dev->name, dev->netdev_ops->ndo_start_xmit);
+
+	}
+
+	if (status != NETDEV_TX_OK) {
+		skb_queue_tail(&npinfo->txq, skb);
+		schedule_delayed_work(&npinfo->tx_work,0);
+	}
+}
+EXPORT_SYMBOL(netpoll_send_skb_on_dev);
+
+void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
+{
+	int total_len, ip_len, udp_len;
+	struct sk_buff *skb;
+	struct udphdr *udph;
+	struct iphdr *iph;
+	struct ethhdr *eth;
+	static atomic_t ip_ident;
+	struct ipv6hdr *ip6h;
+
+	udp_len = len + sizeof(*udph);
+	if (np->ipv6)
+		ip_len = udp_len + sizeof(*ip6h);
+	else
+		ip_len = udp_len + sizeof(*iph);
+
+	total_len = ip_len + LL_RESERVED_SPACE(np->dev);
+
+	skb = find_skb(np, total_len + np->dev->needed_tailroom,
+		       total_len - len);
+	if (!skb)
+		return;
+
+	skb_copy_to_linear_data(skb, msg, len);
+	skb_put(skb, len);
+
+	skb_push(skb, sizeof(*udph));
+	skb_reset_transport_header(skb);
+	udph = udp_hdr(skb);
+	udph->source = htons(np->local_port);
+	udph->dest = htons(np->remote_port);
+	udph->len = htons(udp_len);
+
+	if (np->ipv6) {
+		udph->check = 0;
+		udph->check = csum_ipv6_magic(&np->local_ip.in6,
+					      &np->remote_ip.in6,
+					      udp_len, IPPROTO_UDP,
+					      csum_partial(udph, udp_len, 0));
+		if (udph->check == 0)
+			udph->check = CSUM_MANGLED_0;
+
+		skb_push(skb, sizeof(*ip6h));
+		skb_reset_network_header(skb);
+		ip6h = ipv6_hdr(skb);
+
+		/* ip6h->version = 6; ip6h->priority = 0; */
+		put_unaligned(0x60, (unsigned char *)ip6h);
+		ip6h->flow_lbl[0] = 0;
+		ip6h->flow_lbl[1] = 0;
+		ip6h->flow_lbl[2] = 0;
+
+		ip6h->payload_len = htons(sizeof(struct udphdr) + len);
+		ip6h->nexthdr = IPPROTO_UDP;
+		ip6h->hop_limit = 32;
+		ip6h->saddr = np->local_ip.in6;
+		ip6h->daddr = np->remote_ip.in6;
+
+		eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
+		skb_reset_mac_header(skb);
+		skb->protocol = eth->h_proto = htons(ETH_P_IPV6);
+	} else {
+		udph->check = 0;
+		udph->check = csum_tcpudp_magic(np->local_ip.ip,
+						np->remote_ip.ip,
+						udp_len, IPPROTO_UDP,
+						csum_partial(udph, udp_len, 0));
+		if (udph->check == 0)
+			udph->check = CSUM_MANGLED_0;
+
+		skb_push(skb, sizeof(*iph));
+		skb_reset_network_header(skb);
+		iph = ip_hdr(skb);
+
+		/* iph->version = 4; iph->ihl = 5; */
+		put_unaligned(0x45, (unsigned char *)iph);
+		iph->tos      = 0;
+		put_unaligned(htons(ip_len), &(iph->tot_len));
+		iph->id       = htons(atomic_inc_return(&ip_ident));
+		iph->frag_off = 0;
+		iph->ttl      = 64;
+		iph->protocol = IPPROTO_UDP;
+		iph->check    = 0;
+		put_unaligned(np->local_ip.ip, &(iph->saddr));
+		put_unaligned(np->remote_ip.ip, &(iph->daddr));
+		iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
+
+		eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
+		skb_reset_mac_header(skb);
+		skb->protocol = eth->h_proto = htons(ETH_P_IP);
+	}
+
+	ether_addr_copy(eth->h_source, np->dev->dev_addr);
+	ether_addr_copy(eth->h_dest, np->remote_mac);
+
+	skb->dev = np->dev;
+
+	netpoll_send_skb(np, skb);
+}
+EXPORT_SYMBOL(netpoll_send_udp);
+
+void netpoll_print_options(struct netpoll *np)
+{
+	np_info(np, "local port %d\n", np->local_port);
+	if (np->ipv6)
+		np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
+	else
+		np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip);
+	np_info(np, "interface '%s'\n", np->dev_name);
+	np_info(np, "remote port %d\n", np->remote_port);
+	if (np->ipv6)
+		np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
+	else
+		np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
+	np_info(np, "remote ethernet address %pM\n", np->remote_mac);
+}
+EXPORT_SYMBOL(netpoll_print_options);
+
+static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
+{
+	const char *end;
+
+	if (!strchr(str, ':') &&
+	    in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
+		if (!*end)
+			return 0;
+	}
+	if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
+#if IS_ENABLED(CONFIG_IPV6)
+		if (!*end)
+			return 1;
+#else
+		return -1;
+#endif
+	}
+	return -1;
+}
+
+int netpoll_parse_options(struct netpoll *np, char *opt)
+{
+	char *cur=opt, *delim;
+	int ipv6;
+	bool ipversion_set = false;
+
+	if (*cur != '@') {
+		if ((delim = strchr(cur, '@')) == NULL)
+			goto parse_failed;
+		*delim = 0;
+		if (kstrtou16(cur, 10, &np->local_port))
+			goto parse_failed;
+		cur = delim;
+	}
+	cur++;
+
+	if (*cur != '/') {
+		ipversion_set = true;
+		if ((delim = strchr(cur, '/')) == NULL)
+			goto parse_failed;
+		*delim = 0;
+		ipv6 = netpoll_parse_ip_addr(cur, &np->local_ip);
+		if (ipv6 < 0)
+			goto parse_failed;
+		else
+			np->ipv6 = (bool)ipv6;
+		cur = delim;
+	}
+	cur++;
+
+	if (*cur != ',') {
+		/* parse out dev name */
+		if ((delim = strchr(cur, ',')) == NULL)
+			goto parse_failed;
+		*delim = 0;
+		strlcpy(np->dev_name, cur, sizeof(np->dev_name));
+		cur = delim;
+	}
+	cur++;
+
+	if (*cur != '@') {
+		/* dst port */
+		if ((delim = strchr(cur, '@')) == NULL)
+			goto parse_failed;
+		*delim = 0;
+		if (*cur == ' ' || *cur == '\t')
+			np_info(np, "warning: whitespace is not allowed\n");
+		if (kstrtou16(cur, 10, &np->remote_port))
+			goto parse_failed;
+		cur = delim;
+	}
+	cur++;
+
+	/* dst ip */
+	if ((delim = strchr(cur, '/')) == NULL)
+		goto parse_failed;
+	*delim = 0;
+	ipv6 = netpoll_parse_ip_addr(cur, &np->remote_ip);
+	if (ipv6 < 0)
+		goto parse_failed;
+	else if (ipversion_set && np->ipv6 != (bool)ipv6)
+		goto parse_failed;
+	else
+		np->ipv6 = (bool)ipv6;
+	cur = delim + 1;
+
+	if (*cur != 0) {
+		/* MAC address */
+		if (!mac_pton(cur, np->remote_mac))
+			goto parse_failed;
+	}
+
+	netpoll_print_options(np);
+
+	return 0;
+
+ parse_failed:
+	np_info(np, "couldn't parse config at '%s'!\n", cur);
+	return -1;
+}
+EXPORT_SYMBOL(netpoll_parse_options);
+
+int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
+{
+	struct netpoll_info *npinfo;
+	const struct net_device_ops *ops;
+	int err;
+
+	np->dev = ndev;
+	strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
+	INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
+
+	if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
+	    !ndev->netdev_ops->ndo_poll_controller) {
+		np_err(np, "%s doesn't support polling, aborting\n",
+		       np->dev_name);
+		err = -ENOTSUPP;
+		goto out;
+	}
+
+	if (!ndev->npinfo) {
+		npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
+		if (!npinfo) {
+			err = -ENOMEM;
+			goto out;
+		}
+
+		sema_init(&npinfo->dev_lock, 1);
+		skb_queue_head_init(&npinfo->txq);
+		INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
+
+		atomic_set(&npinfo->refcnt, 1);
+
+		ops = np->dev->netdev_ops;
+		if (ops->ndo_netpoll_setup) {
+			err = ops->ndo_netpoll_setup(ndev, npinfo);
+			if (err)
+				goto free_npinfo;
+		}
+	} else {
+		npinfo = rtnl_dereference(ndev->npinfo);
+		atomic_inc(&npinfo->refcnt);
+	}
+
+	npinfo->netpoll = np;
+
+	/* last thing to do is link it to the net device structure */
+	rcu_assign_pointer(ndev->npinfo, npinfo);
+
+	return 0;
+
+free_npinfo:
+	kfree(npinfo);
+out:
+	return err;
+}
+EXPORT_SYMBOL_GPL(__netpoll_setup);
+
+int netpoll_setup(struct netpoll *np)
+{
+	struct net_device *ndev = NULL;
+	struct in_device *in_dev;
+	int err;
+
+	rtnl_lock();
+	if (np->dev_name) {
+		struct net *net = current->nsproxy->net_ns;
+		ndev = __dev_get_by_name(net, np->dev_name);
+	}
+	if (!ndev) {
+		np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
+		err = -ENODEV;
+		goto unlock;
+	}
+	dev_hold(ndev);
+
+	if (netdev_master_upper_dev_get(ndev)) {
+		np_err(np, "%s is a slave device, aborting\n", np->dev_name);
+		err = -EBUSY;
+		goto put;
+	}
+
+	if (!netif_running(ndev)) {
+		unsigned long atmost, atleast;
+
+		np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
+
+		err = dev_open(ndev);
+
+		if (err) {
+			np_err(np, "failed to open %s\n", ndev->name);
+			goto put;
+		}
+
+		rtnl_unlock();
+		atleast = jiffies + HZ/10;
+		atmost = jiffies + carrier_timeout * HZ;
+		while (!netif_carrier_ok(ndev)) {
+			if (time_after(jiffies, atmost)) {
+				np_notice(np, "timeout waiting for carrier\n");
+				break;
+			}
+			msleep(1);
+		}
+
+		/* If carrier appears to come up instantly, we don't
+		 * trust it and pause so that we don't pump all our
+		 * queued console messages into the bitbucket.
+		 */
+
+		if (time_before(jiffies, atleast)) {
+			np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
+			msleep(4000);
+		}
+		rtnl_lock();
+	}
+
+	if (!np->local_ip.ip) {
+		if (!np->ipv6) {
+			in_dev = __in_dev_get_rtnl(ndev);
+
+			if (!in_dev || !in_dev->ifa_list) {
+				np_err(np, "no IP address for %s, aborting\n",
+				       np->dev_name);
+				err = -EDESTADDRREQ;
+				goto put;
+			}
+
+			np->local_ip.ip = in_dev->ifa_list->ifa_local;
+			np_info(np, "local IP %pI4\n", &np->local_ip.ip);
+		} else {
+#if IS_ENABLED(CONFIG_IPV6)
+			struct inet6_dev *idev;
+
+			err = -EDESTADDRREQ;
+			idev = __in6_dev_get(ndev);
+			if (idev) {
+				struct inet6_ifaddr *ifp;
+
+				read_lock_bh(&idev->lock);
+				list_for_each_entry(ifp, &idev->addr_list, if_list) {
+					if (ipv6_addr_type(&ifp->addr) & IPV6_ADDR_LINKLOCAL)
+						continue;
+					np->local_ip.in6 = ifp->addr;
+					err = 0;
+					break;
+				}
+				read_unlock_bh(&idev->lock);
+			}
+			if (err) {
+				np_err(np, "no IPv6 address for %s, aborting\n",
+				       np->dev_name);
+				goto put;
+			} else
+				np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
+#else
+			np_err(np, "IPv6 is not supported %s, aborting\n",
+			       np->dev_name);
+			err = -EINVAL;
+			goto put;
+#endif
+		}
+	}
+
+	/* fill up the skb queue */
+	refill_skbs();
+
+	err = __netpoll_setup(np, ndev);
+	if (err)
+		goto put;
+
+	rtnl_unlock();
+	return 0;
+
+put:
+	dev_put(ndev);
+unlock:
+	rtnl_unlock();
+	return err;
+}
+EXPORT_SYMBOL(netpoll_setup);
+
+static int __init netpoll_init(void)
+{
+	skb_queue_head_init(&skb_pool);
+	return 0;
+}
+core_initcall(netpoll_init);
+
+static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
+{
+	struct netpoll_info *npinfo =
+			container_of(rcu_head, struct netpoll_info, rcu);
+
+	skb_queue_purge(&npinfo->txq);
+
+	/* we can't call cancel_delayed_work_sync here, as we are in softirq */
+	cancel_delayed_work(&npinfo->tx_work);
+
+	/* clean after last, unfinished work */
+	__skb_queue_purge(&npinfo->txq);
+	/* now cancel it again */
+	cancel_delayed_work(&npinfo->tx_work);
+	kfree(npinfo);
+}
+
+void __netpoll_cleanup(struct netpoll *np)
+{
+	struct netpoll_info *npinfo;
+
+	/* rtnl_dereference would be preferable here but
+	 * rcu_cleanup_netpoll path can put us in here safely without
+	 * holding the rtnl, so plain rcu_dereference it is
+	 */
+	npinfo = rtnl_dereference(np->dev->npinfo);
+	if (!npinfo)
+		return;
+
+	synchronize_srcu(&netpoll_srcu);
+
+	if (atomic_dec_and_test(&npinfo->refcnt)) {
+		const struct net_device_ops *ops;
+
+		ops = np->dev->netdev_ops;
+		if (ops->ndo_netpoll_cleanup)
+			ops->ndo_netpoll_cleanup(np->dev);
+
+		RCU_INIT_POINTER(np->dev->npinfo, NULL);
+		call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
+	} else
+		RCU_INIT_POINTER(np->dev->npinfo, NULL);
+}
+EXPORT_SYMBOL_GPL(__netpoll_cleanup);
+
+static void netpoll_async_cleanup(struct work_struct *work)
+{
+	struct netpoll *np = container_of(work, struct netpoll, cleanup_work);
+
+	rtnl_lock();
+	__netpoll_cleanup(np);
+	rtnl_unlock();
+	kfree(np);
+}
+
+void __netpoll_free_async(struct netpoll *np)
+{
+	schedule_work(&np->cleanup_work);
+}
+EXPORT_SYMBOL_GPL(__netpoll_free_async);
+
+void netpoll_cleanup(struct netpoll *np)
+{
+	rtnl_lock();
+	if (!np->dev)
+		goto out;
+	__netpoll_cleanup(np);
+	dev_put(np->dev);
+	np->dev = NULL;
+out:
+	rtnl_unlock();
+}
+EXPORT_SYMBOL(netpoll_cleanup);