53fb95d3c1
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>
94 lines
2.1 KiB
C
94 lines
2.1 KiB
C
/*
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* Common code for low-level network console, dump, and debugger code
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*
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* Derived from netconsole, kgdb-over-ethernet, and netdump patches
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*/
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#ifndef _LINUX_NETPOLL_H
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#define _LINUX_NETPOLL_H
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#include <linux/netdevice.h>
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#include <linux/interrupt.h>
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#include <linux/rcupdate.h>
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#include <linux/list.h>
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struct netpoll;
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struct netpoll {
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struct net_device *dev;
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char dev_name[16], *name;
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void (*rx_hook)(struct netpoll *, int, char *, int);
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void (*drop)(struct sk_buff *skb);
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u32 local_ip, remote_ip;
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u16 local_port, remote_port;
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unsigned char local_mac[6], remote_mac[6];
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};
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struct netpoll_info {
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spinlock_t poll_lock;
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int poll_owner;
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int tries;
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int rx_flags;
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spinlock_t rx_lock;
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struct netpoll *rx_np; /* netpoll that registered an rx_hook */
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};
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void netpoll_poll(struct netpoll *np);
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void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
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int netpoll_parse_options(struct netpoll *np, char *opt);
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int netpoll_setup(struct netpoll *np);
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int netpoll_trap(void);
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void netpoll_set_trap(int trap);
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void netpoll_cleanup(struct netpoll *np);
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int __netpoll_rx(struct sk_buff *skb);
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void netpoll_queue(struct sk_buff *skb);
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#ifdef CONFIG_NETPOLL
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static inline int netpoll_rx(struct sk_buff *skb)
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{
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struct netpoll_info *npinfo = skb->dev->npinfo;
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unsigned long flags;
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int ret = 0;
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if (!npinfo || (!npinfo->rx_np && !npinfo->rx_flags))
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return 0;
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spin_lock_irqsave(&npinfo->rx_lock, flags);
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/* check rx_flags again with the lock held */
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if (npinfo->rx_flags && __netpoll_rx(skb))
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ret = 1;
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spin_unlock_irqrestore(&npinfo->rx_lock, flags);
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return ret;
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}
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static inline void *netpoll_poll_lock(struct net_device *dev)
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{
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rcu_read_lock(); /* deal with race on ->npinfo */
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if (dev->npinfo) {
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spin_lock(&dev->npinfo->poll_lock);
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dev->npinfo->poll_owner = smp_processor_id();
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return dev->npinfo;
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}
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return NULL;
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}
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static inline void netpoll_poll_unlock(void *have)
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{
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struct netpoll_info *npi = have;
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if (npi) {
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npi->poll_owner = -1;
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spin_unlock(&npi->poll_lock);
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}
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rcu_read_unlock();
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}
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#else
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#define netpoll_rx(a) 0
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#define netpoll_poll_lock(a) 0
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#define netpoll_poll_unlock(a)
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#endif
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#endif
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