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![Mark Rutland](/assets/img/avatar_default.png)
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts netlink and netfilter code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Florian Westphal <fw@strlen.de> Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-7-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
129 lines
4.1 KiB
C
129 lines
4.1 KiB
C
#ifndef __LINUX_RTNETLINK_H
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#define __LINUX_RTNETLINK_H
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#include <linux/mutex.h>
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#include <linux/netdevice.h>
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#include <linux/wait.h>
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#include <uapi/linux/rtnetlink.h>
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extern int rtnetlink_send(struct sk_buff *skb, struct net *net, u32 pid, u32 group, int echo);
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extern int rtnl_unicast(struct sk_buff *skb, struct net *net, u32 pid);
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extern void rtnl_notify(struct sk_buff *skb, struct net *net, u32 pid,
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u32 group, struct nlmsghdr *nlh, gfp_t flags);
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extern void rtnl_set_sk_err(struct net *net, u32 group, int error);
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extern int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics);
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extern int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst,
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u32 id, long expires, u32 error);
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void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change, gfp_t flags);
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struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev,
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unsigned change, u32 event,
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gfp_t flags);
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void rtmsg_ifinfo_send(struct sk_buff *skb, struct net_device *dev,
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gfp_t flags);
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/* RTNL is used as a global lock for all changes to network configuration */
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extern void rtnl_lock(void);
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extern void rtnl_unlock(void);
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extern int rtnl_trylock(void);
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extern int rtnl_is_locked(void);
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extern wait_queue_head_t netdev_unregistering_wq;
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extern struct mutex net_mutex;
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#ifdef CONFIG_PROVE_LOCKING
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extern bool lockdep_rtnl_is_held(void);
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#else
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static inline bool lockdep_rtnl_is_held(void)
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{
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return true;
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}
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#endif /* #ifdef CONFIG_PROVE_LOCKING */
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/**
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* rcu_dereference_rtnl - rcu_dereference with debug checking
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* @p: The pointer to read, prior to dereferencing
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*
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* Do an rcu_dereference(p), but check caller either holds rcu_read_lock()
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* or RTNL. Note : Please prefer rtnl_dereference() or rcu_dereference()
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*/
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#define rcu_dereference_rtnl(p) \
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rcu_dereference_check(p, lockdep_rtnl_is_held())
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/**
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* rcu_dereference_bh_rtnl - rcu_dereference_bh with debug checking
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* @p: The pointer to read, prior to dereference
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*
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* Do an rcu_dereference_bh(p), but check caller either holds rcu_read_lock_bh()
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* or RTNL. Note : Please prefer rtnl_dereference() or rcu_dereference_bh()
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*/
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#define rcu_dereference_bh_rtnl(p) \
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rcu_dereference_bh_check(p, lockdep_rtnl_is_held())
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/**
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* rtnl_dereference - fetch RCU pointer when updates are prevented by RTNL
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* @p: The pointer to read, prior to dereferencing
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*
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* Return the value of the specified RCU-protected pointer, but omit
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* both the smp_read_barrier_depends() and the READ_ONCE(), because
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* caller holds RTNL.
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*/
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#define rtnl_dereference(p) \
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rcu_dereference_protected(p, lockdep_rtnl_is_held())
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static inline struct netdev_queue *dev_ingress_queue(struct net_device *dev)
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{
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return rtnl_dereference(dev->ingress_queue);
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}
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struct netdev_queue *dev_ingress_queue_create(struct net_device *dev);
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#ifdef CONFIG_NET_INGRESS
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void net_inc_ingress_queue(void);
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void net_dec_ingress_queue(void);
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#endif
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#ifdef CONFIG_NET_EGRESS
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void net_inc_egress_queue(void);
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void net_dec_egress_queue(void);
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#endif
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void rtnetlink_init(void);
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void __rtnl_unlock(void);
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void rtnl_kfree_skbs(struct sk_buff *head, struct sk_buff *tail);
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#define ASSERT_RTNL() do { \
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if (unlikely(!rtnl_is_locked())) { \
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printk(KERN_ERR "RTNL: assertion failed at %s (%d)\n", \
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__FILE__, __LINE__); \
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dump_stack(); \
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} \
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} while(0)
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extern int ndo_dflt_fdb_dump(struct sk_buff *skb,
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struct netlink_callback *cb,
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struct net_device *dev,
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struct net_device *filter_dev,
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int *idx);
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extern int ndo_dflt_fdb_add(struct ndmsg *ndm,
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struct nlattr *tb[],
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struct net_device *dev,
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const unsigned char *addr,
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u16 vid,
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u16 flags);
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extern int ndo_dflt_fdb_del(struct ndmsg *ndm,
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struct nlattr *tb[],
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struct net_device *dev,
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const unsigned char *addr,
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u16 vid);
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extern int ndo_dflt_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
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struct net_device *dev, u16 mode,
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u32 flags, u32 mask, int nlflags,
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u32 filter_mask,
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int (*vlan_fill)(struct sk_buff *skb,
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struct net_device *dev,
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u32 filter_mask));
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#endif /* __LINUX_RTNETLINK_H */
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