1
linux/net/core/netpoll.c
David S. Miller fd2ea0a79f net: Use queue aware tests throughout.
This effectively "flips the switch" by making the core networking
and multiqueue-aware drivers use the new TX multiqueue structures.

Non-multiqueue drivers need no changes.  The interfaces they use such
as netif_stop_queue() degenerate into an operation on TX queue zero.
So everything "just works" for them.

Code that really wants to do "X" to all TX queues now invokes a
routine that does so, such as netif_tx_wake_all_queues(),
netif_tx_stop_all_queues(), etc.

pktgen and netpoll required a little bit more surgery than the others.

In particular the pktgen changes, whilst functional, could be largely
improved.  The initial check in pktgen_xmit() will sometimes check the
wrong queue, which is mostly harmless.  The thing to do is probably to
invoke fill_packet() earlier.

The bulk of the netpoll changes is to make the code operate solely on
the TX queue indicated by by the SKB queue mapping.

Setting of the SKB queue mapping is entirely confined inside of
net/core/dev.c:dev_pick_tx().  If we end up needing any kind of
special semantics (drops, for example) it will be implemented here.

Finally, we now have a "real_num_tx_queues" which is where the driver
indicates how many TX queues are actually active.

With IGB changes from Jeff Kirsher.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:07 -07:00

850 lines
19 KiB
C

/*
* 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.
*/
#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 <net/tcp.h>
#include <net/udp.h>
#include <asm/unaligned.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
#define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
static struct sk_buff_head skb_pool;
static atomic_t trapped;
#define USEC_PER_POLL 50
#define NETPOLL_RX_ENABLED 1
#define NETPOLL_RX_DROP 2
#define MAX_SKB_SIZE \
(MAX_UDP_CHUNK + sizeof(struct udphdr) + \
sizeof(struct iphdr) + sizeof(struct ethhdr))
static void zap_completion_queue(void);
static void arp_reply(struct sk_buff *skb);
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 = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
local_irq_save(flags);
__netif_tx_lock(txq, smp_processor_id());
if (netif_tx_queue_stopped(txq) ||
dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
skb_queue_head(&npinfo->txq, skb);
__netif_tx_unlock(txq);
local_irq_restore(flags);
schedule_delayed_work(&npinfo->tx_work, HZ/10);
return;
}
__netif_tx_unlock(txq);
local_irq_restore(flags);
}
}
static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
unsigned short ulen, __be32 saddr, __be32 daddr)
{
__wsum psum;
if (uh->check == 0 || skb_csum_unnecessary(skb))
return 0;
psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
if (skb->ip_summed == CHECKSUM_COMPLETE &&
!csum_fold(csum_add(psum, skb->csum)))
return 0;
skb->csum = psum;
return __skb_checksum_complete(skb);
}
/*
* 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.
*
* In cases where there is bi-directional communications, reading only
* one message at a time can lead to packets being dropped by the
* network adapter, forcing superfluous retries and possibly timeouts.
* Thus, we set our budget to greater than 1.
*/
static int poll_one_napi(struct netpoll_info *npinfo,
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;
npinfo->rx_flags |= NETPOLL_RX_DROP;
atomic_inc(&trapped);
work = napi->poll(napi, budget);
atomic_dec(&trapped);
npinfo->rx_flags &= ~NETPOLL_RX_DROP;
return budget - work;
}
static void poll_napi(struct net_device *dev)
{
struct napi_struct *napi;
int budget = 16;
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(dev->npinfo, napi, budget);
spin_unlock(&napi->poll_lock);
if (!budget)
break;
}
}
}
static void service_arp_queue(struct netpoll_info *npi)
{
if (npi) {
struct sk_buff *skb;
while ((skb = skb_dequeue(&npi->arp_tx)))
arp_reply(skb);
}
}
void netpoll_poll(struct netpoll *np)
{
struct net_device *dev = np->dev;
if (!dev || !netif_running(dev) || !dev->poll_controller)
return;
/* Process pending work on NIC */
dev->poll_controller(dev);
poll_napi(dev);
service_arp_queue(dev->npinfo);
zap_completion_queue();
}
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->destructor) {
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(np);
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;
}
static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
{
int status = NETDEV_TX_BUSY;
unsigned long tries;
struct net_device *dev = np->dev;
struct netpoll_info *npinfo = np->dev->npinfo;
if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) {
__kfree_skb(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;
unsigned long flags;
txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
local_irq_save(flags);
/* try until next clock tick */
for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
tries > 0; --tries) {
if (__netif_tx_trylock(txq)) {
if (!netif_tx_queue_stopped(txq))
status = dev->hard_start_xmit(skb, dev);
__netif_tx_unlock(txq);
if (status == NETDEV_TX_OK)
break;
}
/* tickle device maybe there is some cleanup */
netpoll_poll(np);
udelay(USEC_PER_POLL);
}
local_irq_restore(flags);
}
if (status != NETDEV_TX_OK) {
skb_queue_tail(&npinfo->txq, skb);
schedule_delayed_work(&npinfo->tx_work,0);
}
}
void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
{
int total_len, eth_len, ip_len, udp_len;
struct sk_buff *skb;
struct udphdr *udph;
struct iphdr *iph;
struct ethhdr *eth;
udp_len = len + sizeof(*udph);
ip_len = eth_len = udp_len + sizeof(*iph);
total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
skb = find_skb(np, total_len, total_len - len);
if (!skb)
return;
skb_copy_to_linear_data(skb, msg, len);
skb->len += 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);
udph->check = 0;
udph->check = csum_tcpudp_magic(htonl(np->local_ip),
htonl(np->remote_ip),
udp_len, IPPROTO_UDP,
csum_partial((unsigned char *)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 = 0;
iph->frag_off = 0;
iph->ttl = 64;
iph->protocol = IPPROTO_UDP;
iph->check = 0;
put_unaligned(htonl(np->local_ip), &(iph->saddr));
put_unaligned(htonl(np->remote_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);
memcpy(eth->h_source, np->dev->dev_addr, ETH_ALEN);
memcpy(eth->h_dest, np->remote_mac, ETH_ALEN);
skb->dev = np->dev;
netpoll_send_skb(np, skb);
}
static void arp_reply(struct sk_buff *skb)
{
struct netpoll_info *npinfo = skb->dev->npinfo;
struct arphdr *arp;
unsigned char *arp_ptr;
int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
__be32 sip, tip;
unsigned char *sha;
struct sk_buff *send_skb;
struct netpoll *np = NULL;
if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
np = npinfo->rx_np;
if (!np)
return;
/* No arp on this interface */
if (skb->dev->flags & IFF_NOARP)
return;
if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
return;
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
arp = arp_hdr(skb);
if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
arp->ar_pro != htons(ETH_P_IP) ||
arp->ar_op != htons(ARPOP_REQUEST))
return;
arp_ptr = (unsigned char *)(arp+1);
/* save the location of the src hw addr */
sha = arp_ptr;
arp_ptr += skb->dev->addr_len;
memcpy(&sip, arp_ptr, 4);
arp_ptr += 4;
/* if we actually cared about dst hw addr, it would get copied here */
arp_ptr += skb->dev->addr_len;
memcpy(&tip, arp_ptr, 4);
/* Should we ignore arp? */
if (tip != htonl(np->local_ip) ||
ipv4_is_loopback(tip) || ipv4_is_multicast(tip))
return;
size = arp_hdr_len(skb->dev);
send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev),
LL_RESERVED_SPACE(np->dev));
if (!send_skb)
return;
skb_reset_network_header(send_skb);
arp = (struct arphdr *) skb_put(send_skb, size);
send_skb->dev = skb->dev;
send_skb->protocol = htons(ETH_P_ARP);
/* Fill the device header for the ARP frame */
if (dev_hard_header(send_skb, skb->dev, ptype,
sha, np->dev->dev_addr,
send_skb->len) < 0) {
kfree_skb(send_skb);
return;
}
/*
* Fill out the arp protocol part.
*
* we only support ethernet device type,
* which (according to RFC 1390) should always equal 1 (Ethernet).
*/
arp->ar_hrd = htons(np->dev->type);
arp->ar_pro = htons(ETH_P_IP);
arp->ar_hln = np->dev->addr_len;
arp->ar_pln = 4;
arp->ar_op = htons(type);
arp_ptr=(unsigned char *)(arp + 1);
memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
arp_ptr += np->dev->addr_len;
memcpy(arp_ptr, &tip, 4);
arp_ptr += 4;
memcpy(arp_ptr, sha, np->dev->addr_len);
arp_ptr += np->dev->addr_len;
memcpy(arp_ptr, &sip, 4);
netpoll_send_skb(np, send_skb);
}
int __netpoll_rx(struct sk_buff *skb)
{
int proto, len, ulen;
struct iphdr *iph;
struct udphdr *uh;
struct netpoll_info *npi = skb->dev->npinfo;
struct netpoll *np = npi->rx_np;
if (!np)
goto out;
if (skb->dev->type != ARPHRD_ETHER)
goto out;
/* check if netpoll clients need ARP */
if (skb->protocol == htons(ETH_P_ARP) &&
atomic_read(&trapped)) {
skb_queue_tail(&npi->arp_tx, skb);
return 1;
}
proto = ntohs(eth_hdr(skb)->h_proto);
if (proto != ETH_P_IP)
goto out;
if (skb->pkt_type == PACKET_OTHERHOST)
goto out;
if (skb_shared(skb))
goto out;
iph = (struct iphdr *)skb->data;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto out;
if (iph->ihl < 5 || iph->version != 4)
goto out;
if (!pskb_may_pull(skb, iph->ihl*4))
goto out;
if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
goto out;
len = ntohs(iph->tot_len);
if (skb->len < len || len < iph->ihl*4)
goto out;
/*
* Our transport medium may have padded the buffer out.
* Now We trim to the true length of the frame.
*/
if (pskb_trim_rcsum(skb, len))
goto out;
if (iph->protocol != IPPROTO_UDP)
goto out;
len -= iph->ihl*4;
uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
ulen = ntohs(uh->len);
if (ulen != len)
goto out;
if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr))
goto out;
if (np->local_ip && np->local_ip != ntohl(iph->daddr))
goto out;
if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
goto out;
if (np->local_port && np->local_port != ntohs(uh->dest))
goto out;
np->rx_hook(np, ntohs(uh->source),
(char *)(uh+1),
ulen - sizeof(struct udphdr));
kfree_skb(skb);
return 1;
out:
if (atomic_read(&trapped)) {
kfree_skb(skb);
return 1;
}
return 0;
}
void netpoll_print_options(struct netpoll *np)
{
DECLARE_MAC_BUF(mac);
printk(KERN_INFO "%s: local port %d\n",
np->name, np->local_port);
printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
np->name, HIPQUAD(np->local_ip));
printk(KERN_INFO "%s: interface %s\n",
np->name, np->dev_name);
printk(KERN_INFO "%s: remote port %d\n",
np->name, np->remote_port);
printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
np->name, HIPQUAD(np->remote_ip));
printk(KERN_INFO "%s: remote ethernet address %s\n",
np->name, print_mac(mac, np->remote_mac));
}
int netpoll_parse_options(struct netpoll *np, char *opt)
{
char *cur=opt, *delim;
if (*cur != '@') {
if ((delim = strchr(cur, '@')) == NULL)
goto parse_failed;
*delim = 0;
np->local_port = simple_strtol(cur, NULL, 10);
cur = delim;
}
cur++;
if (*cur != '/') {
if ((delim = strchr(cur, '/')) == NULL)
goto parse_failed;
*delim = 0;
np->local_ip = ntohl(in_aton(cur));
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;
np->remote_port = simple_strtol(cur, NULL, 10);
cur = delim;
}
cur++;
/* dst ip */
if ((delim = strchr(cur, '/')) == NULL)
goto parse_failed;
*delim = 0;
np->remote_ip = ntohl(in_aton(cur));
cur = delim + 1;
if (*cur != 0) {
/* MAC address */
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim = 0;
np->remote_mac[0] = simple_strtol(cur, NULL, 16);
cur = delim + 1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim = 0;
np->remote_mac[1] = simple_strtol(cur, NULL, 16);
cur = delim + 1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim = 0;
np->remote_mac[2] = simple_strtol(cur, NULL, 16);
cur = delim + 1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim = 0;
np->remote_mac[3] = simple_strtol(cur, NULL, 16);
cur = delim + 1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim = 0;
np->remote_mac[4] = simple_strtol(cur, NULL, 16);
cur = delim + 1;
np->remote_mac[5] = simple_strtol(cur, NULL, 16);
}
netpoll_print_options(np);
return 0;
parse_failed:
printk(KERN_INFO "%s: couldn't parse config at %s!\n",
np->name, cur);
return -1;
}
int netpoll_setup(struct netpoll *np)
{
struct net_device *ndev = NULL;
struct in_device *in_dev;
struct netpoll_info *npinfo;
unsigned long flags;
int err;
if (np->dev_name)
ndev = dev_get_by_name(&init_net, np->dev_name);
if (!ndev) {
printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
np->name, np->dev_name);
return -ENODEV;
}
np->dev = ndev;
if (!ndev->npinfo) {
npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
if (!npinfo) {
err = -ENOMEM;
goto release;
}
npinfo->rx_flags = 0;
npinfo->rx_np = NULL;
spin_lock_init(&npinfo->rx_lock);
skb_queue_head_init(&npinfo->arp_tx);
skb_queue_head_init(&npinfo->txq);
INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
atomic_set(&npinfo->refcnt, 1);
} else {
npinfo = ndev->npinfo;
atomic_inc(&npinfo->refcnt);
}
if (!ndev->poll_controller) {
printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
np->name, np->dev_name);
err = -ENOTSUPP;
goto release;
}
if (!netif_running(ndev)) {
unsigned long atmost, atleast;
printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
np->name, np->dev_name);
rtnl_lock();
err = dev_open(ndev);
rtnl_unlock();
if (err) {
printk(KERN_ERR "%s: failed to open %s\n",
np->name, ndev->name);
goto release;
}
atleast = jiffies + HZ/10;
atmost = jiffies + 4*HZ;
while (!netif_carrier_ok(ndev)) {
if (time_after(jiffies, atmost)) {
printk(KERN_NOTICE
"%s: timeout waiting for carrier\n",
np->name);
break;
}
cond_resched();
}
/* 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)) {
printk(KERN_NOTICE "%s: carrier detect appears"
" untrustworthy, waiting 4 seconds\n",
np->name);
msleep(4000);
}
}
if (!np->local_ip) {
rcu_read_lock();
in_dev = __in_dev_get_rcu(ndev);
if (!in_dev || !in_dev->ifa_list) {
rcu_read_unlock();
printk(KERN_ERR "%s: no IP address for %s, aborting\n",
np->name, np->dev_name);
err = -EDESTADDRREQ;
goto release;
}
np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
rcu_read_unlock();
printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
np->name, HIPQUAD(np->local_ip));
}
if (np->rx_hook) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
npinfo->rx_flags |= NETPOLL_RX_ENABLED;
npinfo->rx_np = np;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
/* fill up the skb queue */
refill_skbs();
/* last thing to do is link it to the net device structure */
ndev->npinfo = npinfo;
/* avoid racing with NAPI reading npinfo */
synchronize_rcu();
return 0;
release:
if (!ndev->npinfo)
kfree(npinfo);
np->dev = NULL;
dev_put(ndev);
return err;
}
static int __init netpoll_init(void)
{
skb_queue_head_init(&skb_pool);
return 0;
}
core_initcall(netpoll_init);
void netpoll_cleanup(struct netpoll *np)
{
struct netpoll_info *npinfo;
unsigned long flags;
if (np->dev) {
npinfo = np->dev->npinfo;
if (npinfo) {
if (npinfo->rx_np == np) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
npinfo->rx_np = NULL;
npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
if (atomic_dec_and_test(&npinfo->refcnt)) {
skb_queue_purge(&npinfo->arp_tx);
skb_queue_purge(&npinfo->txq);
cancel_rearming_delayed_work(&npinfo->tx_work);
/* clean after last, unfinished work */
__skb_queue_purge(&npinfo->txq);
kfree(npinfo);
np->dev->npinfo = NULL;
}
}
dev_put(np->dev);
}
np->dev = NULL;
}
int netpoll_trap(void)
{
return atomic_read(&trapped);
}
void netpoll_set_trap(int trap)
{
if (trap)
atomic_inc(&trapped);
else
atomic_dec(&trapped);
}
EXPORT_SYMBOL(netpoll_set_trap);
EXPORT_SYMBOL(netpoll_trap);
EXPORT_SYMBOL(netpoll_print_options);
EXPORT_SYMBOL(netpoll_parse_options);
EXPORT_SYMBOL(netpoll_setup);
EXPORT_SYMBOL(netpoll_cleanup);
EXPORT_SYMBOL(netpoll_send_udp);
EXPORT_SYMBOL(netpoll_poll);