kernel-ark/include/linux/netpoll.h
Matt Mackall 53fb95d3c1 [NETPOLL]: fix initialization/NAPI race
This fixes a race during initialization with the NAPI softirq
processing by using an RCU approach.

This race was discovered when refill_skbs() was added to
the setup code.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-11 19:27:43 -07:00

94 lines
2.1 KiB
C

/*
* Common code for low-level network console, dump, and debugger code
*
* Derived from netconsole, kgdb-over-ethernet, and netdump patches
*/
#ifndef _LINUX_NETPOLL_H
#define _LINUX_NETPOLL_H
#include <linux/netdevice.h>
#include <linux/interrupt.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
struct netpoll;
struct netpoll {
struct net_device *dev;
char dev_name[16], *name;
void (*rx_hook)(struct netpoll *, int, char *, int);
void (*drop)(struct sk_buff *skb);
u32 local_ip, remote_ip;
u16 local_port, remote_port;
unsigned char local_mac[6], remote_mac[6];
};
struct netpoll_info {
spinlock_t poll_lock;
int poll_owner;
int tries;
int rx_flags;
spinlock_t rx_lock;
struct netpoll *rx_np; /* netpoll that registered an rx_hook */
};
void netpoll_poll(struct netpoll *np);
void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
int netpoll_parse_options(struct netpoll *np, char *opt);
int netpoll_setup(struct netpoll *np);
int netpoll_trap(void);
void netpoll_set_trap(int trap);
void netpoll_cleanup(struct netpoll *np);
int __netpoll_rx(struct sk_buff *skb);
void netpoll_queue(struct sk_buff *skb);
#ifdef CONFIG_NETPOLL
static inline int netpoll_rx(struct sk_buff *skb)
{
struct netpoll_info *npinfo = skb->dev->npinfo;
unsigned long flags;
int ret = 0;
if (!npinfo || (!npinfo->rx_np && !npinfo->rx_flags))
return 0;
spin_lock_irqsave(&npinfo->rx_lock, flags);
/* check rx_flags again with the lock held */
if (npinfo->rx_flags && __netpoll_rx(skb))
ret = 1;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
return ret;
}
static inline void *netpoll_poll_lock(struct net_device *dev)
{
rcu_read_lock(); /* deal with race on ->npinfo */
if (dev->npinfo) {
spin_lock(&dev->npinfo->poll_lock);
dev->npinfo->poll_owner = smp_processor_id();
return dev->npinfo;
}
return NULL;
}
static inline void netpoll_poll_unlock(void *have)
{
struct netpoll_info *npi = have;
if (npi) {
npi->poll_owner = -1;
spin_unlock(&npi->poll_lock);
}
rcu_read_unlock();
}
#else
#define netpoll_rx(a) 0
#define netpoll_poll_lock(a) 0
#define netpoll_poll_unlock(a)
#endif
#endif