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https://github.com/edk2-porting/linux-next.git
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f0b07bb151
rtnl_lock() is used everywhere, and contention is very high. When someone wants to iterate over alive net namespaces, he/she has no a possibility to do that without exclusive lock. But the exclusive rtnl_lock() in such places is overkill, and it just increases the contention. Yes, there is already for_each_net_rcu() in kernel, but it requires rcu_read_lock(), and this can't be sleepable. Also, sometimes it may be need really prevent net_namespace_list growth, so for_each_net_rcu() is not fit there. This patch introduces new rw_semaphore, which will be used instead of rtnl_mutex to protect net_namespace_list. It is sleepable and allows not-exclusive iterations over net namespaces list. It allows to stop using rtnl_lock() in several places (what is made in next patches) and makes less the time, we keep rtnl_mutex. Here we just add new lock, while the explanation of we can remove rtnl_lock() there are in next patches. Fine grained locks generally are better, then one big lock, so let's do that with net_namespace_list, while the situation allows that. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net>
131 lines
4.2 KiB
C
131 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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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void rtmsg_ifinfo_newnet(int type, struct net_device *dev, unsigned int change,
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gfp_t flags, int *new_nsid, int new_ifindex);
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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, int *new_nsid,
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int new_ifindex);
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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 int rtnl_lock_killable(void);
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extern wait_queue_head_t netdev_unregistering_wq;
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extern struct rw_semaphore pernet_ops_rwsem;
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extern struct rw_semaphore net_rwsem;
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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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* the READ_ONCE(), because 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() \
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WARN_ONCE(!rtnl_is_locked(), \
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"RTNL: assertion failed at %s (%d)\n", __FILE__, __LINE__)
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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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