diff options
| -rw-r--r-- | include/linux/rtnetlink.h | 21 | ||||
| -rw-r--r-- | include/net/net_namespace.h | 4 | ||||
| -rw-r--r-- | net/Kconfig.debug | 15 | ||||
| -rw-r--r-- | net/core/net_namespace.c | 6 | ||||
| -rw-r--r-- | net/core/rtnetlink.c | 58 |
5 files changed, 104 insertions, 0 deletions
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index cdfc897f1e3c..edd840a49989 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -92,6 +92,27 @@ static inline bool lockdep_rtnl_is_held(void) #define rcu_replace_pointer_rtnl(rp, p) \ rcu_replace_pointer(rp, p, lockdep_rtnl_is_held()) +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL +void __rtnl_net_lock(struct net *net); +void __rtnl_net_unlock(struct net *net); +void rtnl_net_lock(struct net *net); +void rtnl_net_unlock(struct net *net); +int rtnl_net_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b); +#else +static inline void __rtnl_net_lock(struct net *net) {} +static inline void __rtnl_net_unlock(struct net *net) {} + +static inline void rtnl_net_lock(struct net *net) +{ + rtnl_lock(); +} + +static inline void rtnl_net_unlock(struct net *net) +{ + rtnl_unlock(); +} +#endif + static inline struct netdev_queue *dev_ingress_queue(struct net_device *dev) { return rtnl_dereference(dev->ingress_queue); diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index e67b483cc8bb..873c0f9fdac6 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -188,6 +188,10 @@ struct net { #if IS_ENABLED(CONFIG_SMC) struct netns_smc smc; #endif +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL + /* Move to a better place when the config guard is removed. */ + struct mutex rtnl_mutex; +#endif } __randomize_layout; #include <linux/seq_file_net.h> diff --git a/net/Kconfig.debug b/net/Kconfig.debug index 5e3fffe707dd..277fab8c4d77 100644 --- a/net/Kconfig.debug +++ b/net/Kconfig.debug @@ -24,3 +24,18 @@ config DEBUG_NET help Enable extra sanity checks in networking. This is mostly used by fuzzers, but is safe to select. + +config DEBUG_NET_SMALL_RTNL + bool "Add extra per-netns mutex inside RTNL" + depends on DEBUG_KERNEL && NET && LOCK_DEBUGGING_SUPPORT + select PROVE_LOCKING + default n + help + rtnl_lock() is being replaced with rtnl_net_lock() that + acquires the global RTNL and a small per-netns RTNL mutex. + + During the conversion, rtnl_net_lock() just adds an extra + mutex in every RTNL scope and slows down the operations. + + Once the conversion completes, rtnl_lock() will be removed + and rtnetlink will gain per-netns scalability. diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index e39479f1c9a4..105e3cd26763 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -334,6 +334,12 @@ static __net_init void preinit_net(struct net *net, struct user_namespace *user_ idr_init(&net->netns_ids); spin_lock_init(&net->nsid_lock); mutex_init(&net->ipv4.ra_mutex); + +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL + mutex_init(&net->rtnl_mutex); + lock_set_cmp_fn(&net->rtnl_mutex, rtnl_net_lock_cmp_fn, NULL); +#endif + preinit_net_sysctl(net); } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 682d8d3127db..46567fa54e42 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -179,6 +179,64 @@ bool lockdep_rtnl_is_held(void) EXPORT_SYMBOL(lockdep_rtnl_is_held); #endif /* #ifdef CONFIG_PROVE_LOCKING */ +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL +void __rtnl_net_lock(struct net *net) +{ + ASSERT_RTNL(); + + mutex_lock(&net->rtnl_mutex); +} +EXPORT_SYMBOL(__rtnl_net_lock); + +void __rtnl_net_unlock(struct net *net) +{ + ASSERT_RTNL(); + + mutex_unlock(&net->rtnl_mutex); +} +EXPORT_SYMBOL(__rtnl_net_unlock); + +void rtnl_net_lock(struct net *net) +{ + rtnl_lock(); + __rtnl_net_lock(net); +} +EXPORT_SYMBOL(rtnl_net_lock); + +void rtnl_net_unlock(struct net *net) +{ + __rtnl_net_unlock(net); + rtnl_unlock(); +} +EXPORT_SYMBOL(rtnl_net_unlock); + +static int rtnl_net_cmp_locks(const struct net *net_a, const struct net *net_b) +{ + if (net_eq(net_a, net_b)) + return 0; + + /* always init_net first */ + if (net_eq(net_a, &init_net)) + return -1; + + if (net_eq(net_b, &init_net)) + return 1; + + /* otherwise lock in ascending order */ + return net_a < net_b ? -1 : 1; +} + +int rtnl_net_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b) +{ + const struct net *net_a, *net_b; + + net_a = container_of(a, struct net, rtnl_mutex.dep_map); + net_b = container_of(b, struct net, rtnl_mutex.dep_map); + + return rtnl_net_cmp_locks(net_a, net_b); +} +#endif + static struct rtnl_link __rcu *__rcu *rtnl_msg_handlers[RTNL_FAMILY_MAX + 1]; static inline int rtm_msgindex(int msgtype) |