1 files changed, 331 insertions, 332 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 9be762e1d042..09f72f10813c 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -34,7 +34,7 @@
 #include <net/addrconf.h>
 #include <net/ndisc.h>
 #include <net/ip6_checksum.h>
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
 #include <trace/events/napi.h>
 #include <linux/kconfig.h>
 
@@ -45,11 +45,6 @@
 
 #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							\
@@ -63,13 +58,6 @@ static void zap_completion_queue(void);
 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 netdev_tx_t netpoll_start_xmit(struct sk_buff *skb,
 				      struct net_device *dev,
 				      struct netdev_queue *txq)
@@ -137,6 +125,20 @@ static void queue_process(struct work_struct *work)
 	}
 }
 
+static int netif_local_xmit_active(struct net_device *dev)
+{
+	int i;
+
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+
+		if (READ_ONCE(txq->xmit_lock_owner) == smp_processor_id())
+			return 1;
+	}
+
+	return 0;
+}
+
 static void poll_one_napi(struct napi_struct *napi)
 {
 	int work;
@@ -148,7 +150,7 @@ static void poll_one_napi(struct napi_struct *napi)
 	if (test_and_set_bit(NAPI_STATE_NPSVC, &napi->state))
 		return;
 
-	/* We explicilty pass the polling call a budget of 0 to
+	/* We explicitly pass the polling call a budget of 0 to
 	 * indicate that we are clearing the Tx path only.
 	 */
 	work = napi->poll(napi, 0);
@@ -183,7 +185,10 @@ void netpoll_poll_dev(struct net_device *dev)
 	if (!ni || down_trylock(&ni->dev_lock))
 		return;
 
-	if (!netif_running(dev)) {
+	/* Some drivers will take the same locks in poll and xmit,
+	 * we can't poll if local CPU is already in xmit.
+	 */
+	if (!netif_running(dev) || netif_local_xmit_active(dev)) {
 		up(&ni->dev_lock);
 		return;
 	}
@@ -203,41 +208,36 @@ EXPORT_SYMBOL(netpoll_poll_dev);
 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);
+	ni = rtnl_dereference(dev->npinfo);
 	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);
+
+	ni = rtnl_dereference(dev->npinfo);
 	if (ni)
 		up(&ni->dev_lock);
-	rcu_read_unlock();
 }
-EXPORT_SYMBOL(netpoll_poll_enable);
 
-static void refill_skbs(void)
+static void refill_skbs(struct netpoll *np)
 {
+	struct sk_buff_head *skb_pool;
 	struct sk_buff *skb;
-	unsigned long flags;
 
-	spin_lock_irqsave(&skb_pool.lock, flags);
-	while (skb_pool.qlen < MAX_SKBS) {
+	skb_pool = &np->skb_pool;
+
+	while (READ_ONCE(skb_pool->qlen) < MAX_SKBS) {
 		skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
 		if (!skb)
 			break;
 
-		__skb_queue_tail(&skb_pool, skb);
+		skb_queue_tail(skb_pool, skb);
 	}
-	spin_unlock_irqrestore(&skb_pool.lock, flags);
 }
 
 static void zap_completion_queue(void)
@@ -274,12 +274,13 @@ static struct sk_buff *find_skb(struct netpoll *np, int len, int reserve)
 	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) {
+		skb = skb_dequeue(&np->skb_pool);
+		schedule_work(&np->refill_wq);
+	}
 
 	if (!skb) {
 		if (++count < 10) {
@@ -299,7 +300,7 @@ static int netpoll_owner_active(struct net_device *dev)
 	struct napi_struct *napi;
 
 	list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) {
-		if (napi->poll_owner == smp_processor_id())
+		if (READ_ONCE(napi->poll_owner) == smp_processor_id())
 			return 1;
 	}
 	return 0;
@@ -309,6 +310,7 @@ static int netpoll_owner_active(struct net_device *dev)
 static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 {
 	netdev_tx_t status = NETDEV_TX_BUSY;
+	netdev_tx_t ret = NET_XMIT_DROP;
 	struct net_device *dev;
 	unsigned long tries;
 	/* It is up to the caller to keep npinfo alive. */
@@ -317,11 +319,12 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 	lockdep_assert_irqs_disabled();
 
 	dev = np->dev;
+	rcu_read_lock();
 	npinfo = rcu_dereference_bh(dev->npinfo);
 
 	if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
 		dev_kfree_skb_irq(skb);
-		return NET_XMIT_DROP;
+		goto out;
 	}
 
 	/* don't get messages out of order, and no recursion */
@@ -360,7 +363,35 @@ static netdev_tx_t __netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 		skb_queue_tail(&npinfo->txq, skb);
 		schedule_delayed_work(&npinfo->tx_work,0);
 	}
-	return NETDEV_TX_OK;
+	ret = NETDEV_TX_OK;
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
+static void netpoll_udp_checksum(struct netpoll *np, struct sk_buff *skb,
+				 int len)
+{
+	struct udphdr *udph;
+	int udp_len;
+
+	udp_len = len + sizeof(struct udphdr);
+	udph = udp_hdr(skb);
+
+	/* check needs to be set, since it will be consumed in csum_partial */
+	udph->check = 0;
+	if (np->ipv6)
+		udph->check = csum_ipv6_magic(&np->local_ip.in6,
+					      &np->remote_ip.in6,
+					      udp_len, IPPROTO_UDP,
+					      csum_partial(udph, udp_len, 0));
+	else
+		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;
 }
 
 netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
@@ -380,228 +411,141 @@ netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(netpoll_send_skb);
 
-void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
+static void push_ipv6(struct netpoll *np, struct sk_buff *skb, 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;
 
-	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
-		WARN_ON_ONCE(!irqs_disabled());
+	skb_push(skb, sizeof(struct ipv6hdr));
+	skb_reset_network_header(skb);
+	ip6h = ipv6_hdr(skb);
 
-	udp_len = len + sizeof(*udph);
-	if (np->ipv6)
-		ip_len = udp_len + sizeof(*ip6h);
-	else
-		ip_len = udp_len + sizeof(*iph);
+	/* ip6h->version = 6; ip6h->priority = 0; */
+	*(unsigned char *)ip6h = 0x60;
+	ip6h->flow_lbl[0] = 0;
+	ip6h->flow_lbl[1] = 0;
+	ip6h->flow_lbl[2] = 0;
 
-	total_len = ip_len + LL_RESERVED_SPACE(np->dev);
+	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;
 
-	skb = find_skb(np, total_len + np->dev->needed_tailroom,
-		       total_len - len);
-	if (!skb)
-		return;
+	skb->protocol = htons(ETH_P_IPV6);
+}
 
-	skb_copy_to_linear_data(skb, msg, len);
-	skb_put(skb, len);
+static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
+{
+	static atomic_t ip_ident;
+	struct iphdr *iph;
+	int ip_len;
+
+	ip_len = len + sizeof(struct udphdr) + sizeof(struct iphdr);
+
+	skb_push(skb, sizeof(struct iphdr));
+	skb_reset_network_header(skb);
+	iph = ip_hdr(skb);
+
+	/* iph->version = 4; iph->ihl = 5; */
+	*(unsigned char *)iph = 0x45;
+	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);
+	skb->protocol = htons(ETH_P_IP);
+}
 
-	skb_push(skb, sizeof(*udph));
+static void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
+{
+	struct udphdr *udph;
+	int udp_len;
+
+	udp_len = len + sizeof(struct udphdr);
+
+	skb_push(skb, sizeof(struct udphdr));
 	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; */
-		*(unsigned char *)ip6h = 0x60;
-		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 = 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; */
-		*(unsigned char *)iph = 0x45;
-		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 = skb_push(skb, ETH_HLEN);
-		skb_reset_mac_header(skb);
-		skb->protocol = eth->h_proto = htons(ETH_P_IP);
-	}
+	netpoll_udp_checksum(np, skb, len);
+}
 
+static void push_eth(struct netpoll *np, struct sk_buff *skb)
+{
+	struct ethhdr *eth;
+
+	eth = skb_push(skb, ETH_HLEN);
+	skb_reset_mac_header(skb);
 	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);
+	if (np->ipv6)
+		eth->h_proto = htons(ETH_P_IPV6);
+	else
+		eth->h_proto = htons(ETH_P_IP);
 }
-EXPORT_SYMBOL(netpoll_send_udp);
 
-void netpoll_print_options(struct netpoll *np)
+int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 {
-	np_info(np, "local port %d\n", np->local_port);
+	int total_len, ip_len, udp_len;
+	struct sk_buff *skb;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		WARN_ON_ONCE(!irqs_disabled());
+
+	udp_len = len + sizeof(struct udphdr);
 	if (np->ipv6)
-		np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6);
+		ip_len = udp_len + sizeof(struct ipv6hdr);
 	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);
+		ip_len = udp_len + sizeof(struct iphdr);
+
+	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 -ENOMEM;
+
+	skb_copy_to_linear_data(skb, msg, len);
+	skb_put(skb, len);
+
+	push_udp(np, skb, len);
 	if (np->ipv6)
-		np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6);
+		push_ipv6(np, skb, len);
 	else
-		np_info(np, "remote IPv4 address %pI4\n", &np->remote_ip.ip);
-	np_info(np, "remote ethernet address %pM\n", np->remote_mac);
+		push_ipv4(np, skb, len);
+	push_eth(np, skb);
+	skb->dev = np->dev;
+
+	return (int)netpoll_send_skb(np, skb);
 }
-EXPORT_SYMBOL(netpoll_print_options);
+EXPORT_SYMBOL(netpoll_send_udp);
+
 
-static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
+static void skb_pool_flush(struct netpoll *np)
 {
-	const char *end;
+	struct sk_buff_head *skb_pool;
 
-	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;
+	cancel_work_sync(&np->refill_wq);
+	skb_pool = &np->skb_pool;
+	skb_queue_purge_reason(skb_pool, SKB_CONSUMED);
 }
 
-int netpoll_parse_options(struct netpoll *np, char *opt)
+static void refill_skbs_work_handler(struct work_struct *work)
 {
-	char *cur=opt, *delim;
-	int ipv6;
-	bool ipversion_set = false;
+	struct netpoll *np =
+		container_of(work, struct netpoll, refill_wq);
 
-	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;
-		strscpy(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;
+	refill_skbs(np);
 }
-EXPORT_SYMBOL(netpoll_parse_options);
 
 int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 {
@@ -609,17 +553,18 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 	const struct net_device_ops *ops;
 	int err;
 
-	np->dev = ndev;
-	strscpy(np->dev_name, ndev->name, IFNAMSIZ);
+	skb_queue_head_init(&np->skb_pool);
+	INIT_WORK(&np->refill_wq, refill_skbs_work_handler);
 
 	if (ndev->priv_flags & IFF_DISABLE_NETPOLL) {
 		np_err(np, "%s doesn't support polling, aborting\n",
-		       np->dev_name);
+		       ndev->name);
 		err = -ENOTSUPP;
 		goto out;
 	}
 
-	if (!ndev->npinfo) {
+	npinfo = rtnl_dereference(ndev->npinfo);
+	if (!npinfo) {
 		npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
 		if (!npinfo) {
 			err = -ENOMEM;
@@ -632,18 +577,21 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 
 		refcount_set(&npinfo->refcnt, 1);
 
-		ops = np->dev->netdev_ops;
+		ops = ndev->netdev_ops;
 		if (ops->ndo_netpoll_setup) {
-			err = ops->ndo_netpoll_setup(ndev, npinfo);
+			err = ops->ndo_netpoll_setup(ndev);
 			if (err)
 				goto free_npinfo;
 		}
 	} else {
-		npinfo = rtnl_dereference(ndev->npinfo);
 		refcount_inc(&npinfo->refcnt);
 	}
 
-	npinfo->netpoll = np;
+	np->dev = ndev;
+	strscpy(np->dev_name, ndev->name, IFNAMSIZ);
+
+	/* fill up the skb queue */
+	refill_skbs(np);
 
 	/* last thing to do is link it to the net device structure */
 	rcu_assign_pointer(ndev->npinfo, npinfo);
@@ -657,144 +605,187 @@ out:
 }
 EXPORT_SYMBOL_GPL(__netpoll_setup);
 
+/*
+ * Returns a pointer to a string representation of the identifier used
+ * to select the egress interface for the given netpoll instance. buf
+ * must be a buffer of length at least MAC_ADDR_STR_LEN + 1.
+ */
+static char *egress_dev(struct netpoll *np, char *buf)
+{
+	if (np->dev_name[0])
+		return np->dev_name;
+
+	snprintf(buf, MAC_ADDR_STR_LEN, "%pM", np->dev_mac);
+	return buf;
+}
+
+static void netpoll_wait_carrier(struct netpoll *np, struct net_device *ndev,
+				 unsigned int timeout)
+{
+	unsigned long atmost;
+
+	atmost = jiffies + timeout * HZ;
+	while (!netif_carrier_ok(ndev)) {
+		if (time_after(jiffies, atmost)) {
+			np_notice(np, "timeout waiting for carrier\n");
+			break;
+		}
+		msleep(1);
+	}
+}
+
+/*
+ * Take the IPv6 from ndev and populate local_ip structure in netpoll
+ */
+static int netpoll_take_ipv6(struct netpoll *np, struct net_device *ndev)
+{
+	char buf[MAC_ADDR_STR_LEN + 1];
+	int err = -EDESTADDRREQ;
+	struct inet6_dev *idev;
+
+	if (!IS_ENABLED(CONFIG_IPV6)) {
+		np_err(np, "IPv6 is not supported %s, aborting\n",
+		       egress_dev(np, buf));
+		return -EINVAL;
+	}
+
+	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) !=
+				!!(ipv6_addr_type(&np->remote_ip.in6) & IPV6_ADDR_LINKLOCAL))
+				continue;
+			/* Got the IP, let's return */
+			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",
+		       egress_dev(np, buf));
+		return err;
+	}
+
+	np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6);
+	return 0;
+}
+
+/*
+ * Take the IPv4 from ndev and populate local_ip structure in netpoll
+ */
+static int netpoll_take_ipv4(struct netpoll *np, struct net_device *ndev)
+{
+	char buf[MAC_ADDR_STR_LEN + 1];
+	const struct in_ifaddr *ifa;
+	struct in_device *in_dev;
+
+	in_dev = __in_dev_get_rtnl(ndev);
+	if (!in_dev) {
+		np_err(np, "no IP address for %s, aborting\n",
+		       egress_dev(np, buf));
+		return -EDESTADDRREQ;
+	}
+
+	ifa = rtnl_dereference(in_dev->ifa_list);
+	if (!ifa) {
+		np_err(np, "no IP address for %s, aborting\n",
+		       egress_dev(np, buf));
+		return -EDESTADDRREQ;
+	}
+
+	np->local_ip.ip = ifa->ifa_local;
+	np_info(np, "local IP %pI4\n", &np->local_ip.ip);
+
+	return 0;
+}
+
 int netpoll_setup(struct netpoll *np)
 {
+	struct net *net = current->nsproxy->net_ns;
+	char buf[MAC_ADDR_STR_LEN + 1];
 	struct net_device *ndev = NULL;
-	struct in_device *in_dev;
+	bool ip_overwritten = false;
 	int err;
 
 	rtnl_lock();
-	if (np->dev_name[0]) {
-		struct net *net = current->nsproxy->net_ns;
+	if (np->dev_name[0])
 		ndev = __dev_get_by_name(net, np->dev_name);
-	}
+	else if (is_valid_ether_addr(np->dev_mac))
+		ndev = dev_getbyhwaddr(net, ARPHRD_ETHER, np->dev_mac);
+
 	if (!ndev) {
-		np_err(np, "%s doesn't exist, aborting\n", np->dev_name);
+		np_err(np, "%s doesn't exist, aborting\n", egress_dev(np, buf));
 		err = -ENODEV;
 		goto unlock;
 	}
-	dev_hold(ndev);
+	netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL);
 
 	if (netdev_master_upper_dev_get(ndev)) {
-		np_err(np, "%s is a slave device, aborting\n", np->dev_name);
+		np_err(np, "%s is a slave device, aborting\n",
+		       egress_dev(np, buf));
 		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);
+		np_info(np, "device %s not up yet, forcing it\n",
+			egress_dev(np, buf));
 
 		err = dev_open(ndev, NULL);
-
 		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);
-		}
+		netpoll_wait_carrier(np, ndev, carrier_timeout);
 		rtnl_lock();
 	}
 
 	if (!np->local_ip.ip) {
 		if (!np->ipv6) {
-			const struct in_ifaddr *ifa;
-
-			in_dev = __in_dev_get_rtnl(ndev);
-			if (!in_dev)
-				goto put_noaddr;
-
-			ifa = rtnl_dereference(in_dev->ifa_list);
-			if (!ifa) {
-put_noaddr:
-				np_err(np, "no IP address for %s, aborting\n",
-				       np->dev_name);
-				err = -EDESTADDRREQ;
+			err = netpoll_take_ipv4(np, ndev);
+			if (err)
 				goto put;
-			}
-
-			np->local_ip.ip = ifa->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) !=
-					    !!(ipv6_addr_type(&np->remote_ip.in6) & 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);
+			err = netpoll_take_ipv6(np, ndev);
+			if (err)
 				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
 		}
+		ip_overwritten = true;
 	}
 
-	/* fill up the skb queue */
-	refill_skbs();
-
 	err = __netpoll_setup(np, ndev);
 	if (err)
-		goto put;
-	netdev_tracker_alloc(ndev, &np->dev_tracker, GFP_KERNEL);
+		goto flush;
 	rtnl_unlock();
+
+	/* Make sure all NAPI polls which started before dev->npinfo
+	 * was visible have exited before we start calling NAPI poll.
+	 * NAPI skips locking if dev->npinfo is NULL.
+	 */
+	synchronize_rcu();
+
 	return 0;
 
+flush:
+	skb_pool_flush(np);
 put:
-	dev_put(ndev);
+	DEBUG_NET_WARN_ON_ONCE(np->dev);
+	if (ip_overwritten)
+		memset(&np->local_ip, 0, sizeof(np->local_ip));
+	netdev_put(ndev, &np->dev_tracker);
 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 =
@@ -812,7 +803,7 @@ static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
 	kfree(npinfo);
 }
 
-void __netpoll_cleanup(struct netpoll *np)
+static void __netpoll_cleanup(struct netpoll *np)
 {
 	struct netpoll_info *npinfo;
 
@@ -820,8 +811,10 @@ void __netpoll_cleanup(struct netpoll *np)
 	if (!npinfo)
 		return;
 
-	synchronize_srcu(&netpoll_srcu);
-
+	/* At this point, there is a single npinfo instance per netdevice, and
+	 * its refcnt tracks how many netpoll structures are linked to it. We
+	 * only perform npinfo cleanup when the refcnt decrements to zero.
+	 */
 	if (refcount_dec_and_test(&npinfo->refcnt)) {
 		const struct net_device_ops *ops;
 
@@ -831,30 +824,36 @@ void __netpoll_cleanup(struct netpoll *np)
 
 		RCU_INIT_POINTER(np->dev->npinfo, NULL);
 		call_rcu(&npinfo->rcu, rcu_cleanup_netpoll_info);
-	} else
-		RCU_INIT_POINTER(np->dev->npinfo, NULL);
+	}
+
+	skb_pool_flush(np);
 }
-EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 
 void __netpoll_free(struct netpoll *np)
 {
 	ASSERT_RTNL();
 
 	/* Wait for transmitting packets to finish before freeing. */
-	synchronize_rcu();
+	synchronize_net();
 	__netpoll_cleanup(np);
 	kfree(np);
 }
 EXPORT_SYMBOL_GPL(__netpoll_free);
 
+void do_netpoll_cleanup(struct netpoll *np)
+{
+	__netpoll_cleanup(np);
+	netdev_put(np->dev, &np->dev_tracker);
+	np->dev = NULL;
+}
+EXPORT_SYMBOL(do_netpoll_cleanup);
+
 void netpoll_cleanup(struct netpoll *np)
 {
 	rtnl_lock();
 	if (!np->dev)
 		goto out;
-	__netpoll_cleanup(np);
-	netdev_put(np->dev, &np->dev_tracker);
-	np->dev = NULL;
+	do_netpoll_cleanup(np);
 out:
 	rtnl_unlock();
 }