mirror of
https://github.com/edk2-porting/linux-next.git
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89c4b442b7
Callers of netpoll_poll_lock() own NAPI_STATE_SCHED
Callers of netpoll_poll_unlock() have BH blocked between
the NAPI_STATE_SCHED being cleared and poll_lock is released.
We can avoid the spinlock which has no contention, and use cmpxchg()
on poll_owner which we need to set anyway.
This removes a possible lockdep violation after the cited commit,
since sk_busy_loop() re-enables BH before calling busy_poll_stop()
Fixes: 217f697436 ("net: busy-poll: allow preemption in sk_busy_loop()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
122 lines
2.6 KiB
C
122 lines
2.6 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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union inet_addr {
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__u32 all[4];
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__be32 ip;
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__be32 ip6[4];
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struct in_addr in;
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struct in6_addr in6;
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};
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struct netpoll {
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struct net_device *dev;
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char dev_name[IFNAMSIZ];
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const char *name;
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union inet_addr local_ip, remote_ip;
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bool ipv6;
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u16 local_port, remote_port;
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u8 remote_mac[ETH_ALEN];
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struct work_struct cleanup_work;
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};
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struct netpoll_info {
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atomic_t refcnt;
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struct semaphore dev_lock;
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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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struct rcu_head rcu;
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};
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#ifdef CONFIG_NETPOLL
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extern void netpoll_poll_disable(struct net_device *dev);
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extern void netpoll_poll_enable(struct net_device *dev);
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#else
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static inline void netpoll_poll_disable(struct net_device *dev) { return; }
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static inline void netpoll_poll_enable(struct net_device *dev) { return; }
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#endif
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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, struct net_device *ndev);
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int netpoll_setup(struct netpoll *np);
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void __netpoll_cleanup(struct netpoll *np);
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void __netpoll_free_async(struct netpoll *np);
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void netpoll_cleanup(struct netpoll *np);
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void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
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struct net_device *dev);
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static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
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{
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unsigned long flags;
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local_irq_save(flags);
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netpoll_send_skb_on_dev(np, skb, np->dev);
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local_irq_restore(flags);
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}
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#ifdef CONFIG_NETPOLL
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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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int owner = smp_processor_id();
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while (cmpxchg(&napi->poll_owner, -1, owner) != -1)
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cpu_relax();
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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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smp_store_release(&napi->poll_owner, -1);
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}
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static inline bool 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 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 bool netpoll_tx_running(struct net_device *dev)
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{
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return false;
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}
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#endif
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#endif
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