MPLS (re)uses RTNL to protect net->mpls.platform_label, but the lock does not need to be RTNL at all. Let's protect net->mpls.platform_label with a dedicated per-netns mutex. Signed-off-by: Kuniyuki Iwashima --- include/net/netns/mpls.h | 1 + net/mpls/af_mpls.c | 55 ++++++++++++++++++++++++++-------------- net/mpls/internal.h | 7 ++++- 3 files changed, 43 insertions(+), 20 deletions(-) diff --git a/include/net/netns/mpls.h b/include/net/netns/mpls.h index 19ad2574b267..6682e51513ef 100644 --- a/include/net/netns/mpls.h +++ b/include/net/netns/mpls.h @@ -16,6 +16,7 @@ struct netns_mpls { int default_ttl; size_t platform_labels; struct mpls_route __rcu * __rcu *platform_label; + struct mutex platform_mutex; struct ctl_table_header *ctl; }; diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index 49fd15232dbe..d0d047dd2245 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -79,8 +79,8 @@ static struct mpls_route *mpls_route_input(struct net *net, unsigned int index) { struct mpls_route __rcu **platform_label; - platform_label = rtnl_dereference(net->mpls.platform_label); - return rtnl_dereference(platform_label[index]); + platform_label = mpls_dereference(net, net->mpls.platform_label); + return mpls_dereference(net, platform_label[index]); } static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned int index) @@ -578,10 +578,8 @@ static void mpls_route_update(struct net *net, unsigned index, struct mpls_route __rcu **platform_label; struct mpls_route *rt; - ASSERT_RTNL(); - - platform_label = rtnl_dereference(net->mpls.platform_label); - rt = rtnl_dereference(platform_label[index]); + platform_label = mpls_dereference(net, net->mpls.platform_label); + rt = mpls_dereference(net, platform_label[index]); rcu_assign_pointer(platform_label[index], new); mpls_notify_route(net, index, rt, new, info); @@ -1472,8 +1470,6 @@ static struct mpls_dev *mpls_add_dev(struct net_device *dev) int err = -ENOMEM; int i; - ASSERT_RTNL(); - mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); if (!mdev) return ERR_PTR(err); @@ -1633,6 +1629,8 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event, unsigned int flags; int err; + mutex_lock(&net->mpls.platform_mutex); + if (event == NETDEV_REGISTER) { mdev = mpls_add_dev(dev); if (IS_ERR(mdev)) { @@ -1695,9 +1693,11 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event, } out: + mutex_unlock(&net->mpls.platform_mutex); return NOTIFY_OK; err: + mutex_unlock(&net->mpls.platform_mutex); return notifier_from_errno(err); } @@ -1973,6 +1973,7 @@ static int rtm_to_route_config(struct sk_buff *skb, static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { + struct net *net = sock_net(skb->sk); struct mpls_route_config *cfg; int err; @@ -1984,7 +1985,9 @@ static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, if (err < 0) goto out; + mutex_lock(&net->mpls.platform_mutex); err = mpls_route_del(cfg, extack); + mutex_unlock(&net->mpls.platform_mutex); out: kfree(cfg); @@ -1995,6 +1998,7 @@ static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { + struct net *net = sock_net(skb->sk); struct mpls_route_config *cfg; int err; @@ -2006,7 +2010,9 @@ static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, if (err < 0) goto out; + mutex_lock(&net->mpls.platform_mutex); err = mpls_route_add(cfg, extack); + mutex_unlock(&net->mpls.platform_mutex); out: kfree(cfg); @@ -2407,6 +2413,8 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh, u8 n_labels; int err; + mutex_lock(&net->mpls.platform_mutex); + err = mpls_valid_getroute_req(in_skb, in_nlh, tb, extack); if (err < 0) goto errout; @@ -2450,7 +2458,8 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh, goto errout_free; } - return rtnl_unicast(skb, net, portid); + err = rtnl_unicast(skb, net, portid); + goto errout; } if (tb[RTA_NEWDST]) { @@ -2542,12 +2551,14 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh, err = rtnl_unicast(skb, net, portid); errout: + mutex_unlock(&net->mpls.platform_mutex); return err; nla_put_failure: nlmsg_cancel(skb, nlh); err = -EMSGSIZE; errout_free: + mutex_unlock(&net->mpls.platform_mutex); kfree_skb(skb); return err; } @@ -2603,9 +2614,10 @@ static int resize_platform_label_table(struct net *net, size_t limit) lo->addr_len); } - rtnl_lock(); + mutex_lock(&net->mpls.platform_mutex); + /* Remember the original table */ - old = rtnl_dereference(net->mpls.platform_label); + old = mpls_dereference(net, net->mpls.platform_label); old_limit = net->mpls.platform_labels; /* Free any labels beyond the new table */ @@ -2636,7 +2648,7 @@ static int resize_platform_label_table(struct net *net, size_t limit) net->mpls.platform_labels = limit; rcu_assign_pointer(net->mpls.platform_label, labels); - rtnl_unlock(); + mutex_unlock(&net->mpls.platform_mutex); mpls_rt_free(rt2); mpls_rt_free(rt0); @@ -2709,12 +2721,13 @@ static const struct ctl_table mpls_table[] = { }, }; -static int mpls_net_init(struct net *net) +static __net_init int mpls_net_init(struct net *net) { size_t table_size = ARRAY_SIZE(mpls_table); struct ctl_table *table; int i; + mutex_init(&net->mpls.platform_mutex); net->mpls.platform_labels = 0; net->mpls.platform_label = NULL; net->mpls.ip_ttl_propagate = 1; @@ -2740,7 +2753,7 @@ static int mpls_net_init(struct net *net) return 0; } -static void mpls_net_exit(struct net *net) +static __net_exit void mpls_net_exit(struct net *net) { struct mpls_route __rcu **platform_label; size_t platform_labels; @@ -2760,16 +2773,20 @@ static void mpls_net_exit(struct net *net) * As such no additional rcu synchronization is necessary when * freeing the platform_label table. */ - rtnl_lock(); - platform_label = rtnl_dereference(net->mpls.platform_label); + mutex_lock(&net->mpls.platform_mutex); + + platform_label = mpls_dereference(net, net->mpls.platform_label); platform_labels = net->mpls.platform_labels; + for (index = 0; index < platform_labels; index++) { - struct mpls_route *rt = rtnl_dereference(platform_label[index]); - RCU_INIT_POINTER(platform_label[index], NULL); + struct mpls_route *rt; + + rt = mpls_dereference(net, platform_label[index]); mpls_notify_route(net, index, rt, NULL, NULL); mpls_rt_free(rt); } - rtnl_unlock(); + + mutex_unlock(&net->mpls.platform_mutex); kvfree(platform_label); } diff --git a/net/mpls/internal.h b/net/mpls/internal.h index 0df01a5395ee..80cb5bbcd946 100644 --- a/net/mpls/internal.h +++ b/net/mpls/internal.h @@ -185,6 +185,11 @@ static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr * return result; } +#define mpls_dereference(net, p) \ + rcu_dereference_protected( \ + (p), \ + lockdep_is_held(&(net)->mpls.platform_mutex)) + static inline struct mpls_dev *mpls_dev_rcu(const struct net_device *dev) { return rcu_dereference(dev->mpls_ptr); @@ -193,7 +198,7 @@ static inline struct mpls_dev *mpls_dev_rcu(const struct net_device *dev) static inline struct mpls_dev *mpls_dev_get(const struct net *net, const struct net_device *dev) { - return rcu_dereference_rtnl(dev->mpls_ptr); + return mpls_dereference(net, dev->mpls_ptr); } int nla_put_labels(struct sk_buff *skb, int attrtype, u8 labels, -- 2.51.1.851.g4ebd6896fd-goog