f0f9deae9e
We cannot use rcu_dereference_bh safely in netpoll_rx as we may be called with IRQs disabled. We could however simply disable IRQs as that too causes BH to be disabled and is safe in either case. Thanks to John Linville for discovering this bug and providing a patch. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
153 lines
3.3 KiB
C
153 lines
3.3 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 net_device *dev;
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struct net_device *real_dev;
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char dev_name[IFNAMSIZ];
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const char *name;
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void (*rx_hook)(struct netpoll *, int, char *, int);
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__be32 local_ip, remote_ip;
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u16 local_port, remote_port;
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u8 remote_mac[ETH_ALEN];
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struct list_head rx; /* rx_np list element */
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};
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struct netpoll_info {
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atomic_t refcnt;
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int rx_flags;
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spinlock_t rx_lock;
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struct list_head rx_np; /* netpolls that registered an rx_hook */
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struct sk_buff_head arp_tx; /* list of arp requests to reply to */
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struct sk_buff_head txq;
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struct delayed_work tx_work;
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struct netpoll *netpoll;
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};
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void netpoll_poll_dev(struct net_device *dev);
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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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void netpoll_print_options(struct netpoll *np);
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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_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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void netpoll_cleanup(struct netpoll *np);
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int __netpoll_rx(struct sk_buff *skb);
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void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
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#ifdef CONFIG_NETPOLL
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static inline bool netpoll_rx(struct sk_buff *skb)
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{
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struct netpoll_info *npinfo;
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unsigned long flags;
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bool ret = false;
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local_irq_save(flags);
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npinfo = rcu_dereference_bh(skb->dev->npinfo);
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if (!npinfo || (list_empty(&npinfo->rx_np) && !npinfo->rx_flags))
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goto out;
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spin_lock(&npinfo->rx_lock);
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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 = true;
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spin_unlock(&npinfo->rx_lock);
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out:
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local_irq_restore(flags);
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return ret;
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}
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static inline int netpoll_rx_on(struct sk_buff *skb)
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{
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struct netpoll_info *npinfo = rcu_dereference_bh(skb->dev->npinfo);
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return npinfo && (!list_empty(&npinfo->rx_np) || npinfo->rx_flags);
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}
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static inline int netpoll_receive_skb(struct sk_buff *skb)
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{
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if (!list_empty(&skb->dev->napi_list))
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return netpoll_rx(skb);
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return 0;
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}
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static inline void *netpoll_poll_lock(struct napi_struct *napi)
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{
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struct net_device *dev = napi->dev;
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if (dev && dev->npinfo) {
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spin_lock(&napi->poll_lock);
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napi->poll_owner = smp_processor_id();
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return napi;
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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 napi_struct *napi = have;
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if (napi) {
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napi->poll_owner = -1;
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spin_unlock(&napi->poll_lock);
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}
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}
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static inline int netpoll_tx_running(struct net_device *dev)
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{
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return irqs_disabled();
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}
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#else
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static inline bool netpoll_rx(struct sk_buff *skb)
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{
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return 0;
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}
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static inline int netpoll_rx_on(struct sk_buff *skb)
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{
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return 0;
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}
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static inline int netpoll_receive_skb(struct sk_buff *skb)
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{
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return 0;
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}
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static inline void *netpoll_poll_lock(struct napi_struct *napi)
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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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}
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static inline void netpoll_netdev_init(struct net_device *dev)
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{
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}
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static inline int netpoll_tx_running(struct net_device *dev)
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{
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return 0;
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}
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#endif
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#endif
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