net: fib_notifier: make FIB notifier per-netns

Currently all users of FIB notifier only cares about events in init_net.
Later in this patchset, users get interested in other namespaces too.
However, for every registered block user is interested only about one
namespace. Make the FIB notifier registration per-netns and avoid
unnecessary calls of notifier block for other namespaces.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 59 insertions, 70 deletions

diff --git a/net/core/fib_notifier.c b/net/core/fib_notifier.c
index 470a606d5e8d..fbd029425638 100644
--- a/net/core/fib_notifier.c
+++ b/net/core/fib_notifier.c
@@ -12,17 +12,15 @@ static unsigned int fib_notifier_net_id;
 
 struct fib_notifier_net {
 	struct list_head fib_notifier_ops;
+	struct atomic_notifier_head fib_chain;
 };
 
-static ATOMIC_NOTIFIER_HEAD(fib_chain);
-
-int call_fib_notifier(struct notifier_block *nb, struct net *net,
+int call_fib_notifier(struct notifier_block *nb,
 		      enum fib_event_type event_type,
 		      struct fib_notifier_info *info)
 {
 	int err;
 
-	info->net = net;
 	err = nb->notifier_call(nb, event_type, info);
 	return notifier_to_errno(err);
 }
@@ -31,35 +29,29 @@ EXPORT_SYMBOL(call_fib_notifier);
 int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
 		       struct fib_notifier_info *info)
 {
+	struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
 	int err;
 
-	info->net = net;
-	err = atomic_notifier_call_chain(&fib_chain, event_type, info);
+	err = atomic_notifier_call_chain(&fn_net->fib_chain, event_type, info);
 	return notifier_to_errno(err);
 }
 EXPORT_SYMBOL(call_fib_notifiers);
 
-static unsigned int fib_seq_sum(void)
+static unsigned int fib_seq_sum(struct net *net)
 {
-	struct fib_notifier_net *fn_net;
+	struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
 	struct fib_notifier_ops *ops;
 	unsigned int fib_seq = 0;
-	struct net *net;
 
 	rtnl_lock();
-	down_read(&net_rwsem);
-	for_each_net(net) {
-		fn_net = net_generic(net, fib_notifier_net_id);
-		rcu_read_lock();
-		list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
-			if (!try_module_get(ops->owner))
-				continue;
-			fib_seq += ops->fib_seq_read(net);
-			module_put(ops->owner);
-		}
-		rcu_read_unlock();
+	rcu_read_lock();
+	list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
+		if (!try_module_get(ops->owner))
+			continue;
+		fib_seq += ops->fib_seq_read(net);
+		module_put(ops->owner);
 	}
-	up_read(&net_rwsem);
+	rcu_read_unlock();
 	rtnl_unlock();
 
 	return fib_seq;
@@ -69,68 +61,66 @@ static int fib_net_dump(struct net *net, struct notifier_block *nb)
 {
 	struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
 	struct fib_notifier_ops *ops;
+	int err = 0;
 
+	rcu_read_lock();
 	list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
-		int err;
-
 		if (!try_module_get(ops->owner))
 			continue;
 		err = ops->fib_dump(net, nb);
 		module_put(ops->owner);
 		if (err)
-			return err;
+			goto unlock;
 	}
 
-	return 0;
+unlock:
+	rcu_read_unlock();
+
+	return err;
 }
 
-static bool fib_dump_is_consistent(struct notifier_block *nb,
+static bool fib_dump_is_consistent(struct net *net, struct notifier_block *nb,
 				   void (*cb)(struct notifier_block *nb),
 				   unsigned int fib_seq)
 {
-	atomic_notifier_chain_register(&fib_chain, nb);
-	if (fib_seq == fib_seq_sum())
+	struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
+
+	atomic_notifier_chain_register(&fn_net->fib_chain, nb);
+	if (fib_seq == fib_seq_sum(net))
 		return true;
-	atomic_notifier_chain_unregister(&fib_chain, nb);
+	atomic_notifier_chain_unregister(&fn_net->fib_chain, nb);
 	if (cb)
 		cb(nb);
 	return false;
 }
 
 #define FIB_DUMP_MAX_RETRIES 5
-int register_fib_notifier(struct notifier_block *nb,
+int register_fib_notifier(struct net *net, struct notifier_block *nb,
 			  void (*cb)(struct notifier_block *nb))
 {
 	int retries = 0;
 	int err;
 
 	do {
-		unsigned int fib_seq = fib_seq_sum();
-		struct net *net;
-
-		rcu_read_lock();
-		for_each_net_rcu(net) {
-			err = fib_net_dump(net, nb);
-			if (err)
-				goto err_fib_net_dump;
-		}
-		rcu_read_unlock();
-
-		if (fib_dump_is_consistent(nb, cb, fib_seq))
+		unsigned int fib_seq = fib_seq_sum(net);
+
+		err = fib_net_dump(net, nb);
+		if (err)
+			return err;
+
+		if (fib_dump_is_consistent(net, nb, cb, fib_seq))
 			return 0;
 	} while (++retries < FIB_DUMP_MAX_RETRIES);
 
 	return -EBUSY;
-
-err_fib_net_dump:
-	rcu_read_unlock();
-	return err;
 }
 EXPORT_SYMBOL(register_fib_notifier);
 
-int unregister_fib_notifier(struct notifier_block *nb)
+int unregister_fib_notifier(struct net *net, struct notifier_block *nb)
 {
-	return atomic_notifier_chain_unregister(&fib_chain, nb);
+	struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
+
+	return atomic_notifier_chain_unregister(&fn_net->fib_chain, nb);
 }
 EXPORT_SYMBOL(unregister_fib_notifier);
 
@@ -181,6 +171,7 @@ static int __net_init fib_notifier_net_init(struct net *net)
 	struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
 
 	INIT_LIST_HEAD(&fn_net->fib_notifier_ops);
+	ATOMIC_INIT_NOTIFIER_HEAD(&fn_net->fib_chain);
 	return 0;
 }
 
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index dd220ce7ca7a..28cbf07102bc 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -321,7 +321,7 @@ out:
 }
 EXPORT_SYMBOL_GPL(fib_rules_lookup);
 
-static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
+static int call_fib_rule_notifier(struct notifier_block *nb,
 				  enum fib_event_type event_type,
 				  struct fib_rule *rule, int family)
 {
@@ -330,7 +330,7 @@ static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
 		.rule = rule,
 	};
 
-	return call_fib_notifier(nb, net, event_type, &info.info);
+	return call_fib_notifier(nb, event_type, &info.info);
 }
 
 static int call_fib_rule_notifiers(struct net *net,
@@ -359,8 +359,7 @@ int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
 	if (!ops)
 		return -EAFNOSUPPORT;
 	list_for_each_entry_rcu(rule, &ops->rules_list, list)
-		call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule,
-				       family);
+		call_fib_rule_notifier(nb, FIB_EVENT_RULE_ADD, rule, family);
 	rules_ops_put(ops);
 
 	return 0;
diff --git a/net/ipv4/fib_notifier.c b/net/ipv4/fib_notifier.c
index b804ccbdb241..1a128c1346fb 100644
--- a/net/ipv4/fib_notifier.c
+++ b/net/ipv4/fib_notifier.c
@@ -9,12 +9,12 @@
 #include <net/netns/ipv4.h>
 #include <net/ip_fib.h>
 
-int call_fib4_notifier(struct notifier_block *nb, struct net *net,
+int call_fib4_notifier(struct notifier_block *nb,
 		       enum fib_event_type event_type,
 		       struct fib_notifier_info *info)
 {
 	info->family = AF_INET;
-	return call_fib_notifier(nb, net, event_type, info);
+	return call_fib_notifier(nb, event_type, info);
 }
 
 int call_fib4_notifiers(struct net *net, enum fib_event_type event_type,
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 1ab2fb6bb37d..5b600b2a2aa3 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -74,7 +74,7 @@
 #include <trace/events/fib.h>
 #include "fib_lookup.h"
 
-static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
+static int call_fib_entry_notifier(struct notifier_block *nb,
 				   enum fib_event_type event_type, u32 dst,
 				   int dst_len, struct fib_alias *fa)
 {
@@ -86,7 +86,7 @@ static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
 		.type = fa->fa_type,
 		.tb_id = fa->tb_id,
 	};
-	return call_fib4_notifier(nb, net, event_type, &info.info);
+	return call_fib4_notifier(nb, event_type, &info.info);
 }
 
 static int call_fib_entry_notifiers(struct net *net,
@@ -2015,8 +2015,8 @@ void fib_info_notify_update(struct net *net, struct nl_info *info)
 	}
 }
 
-static void fib_leaf_notify(struct net *net, struct key_vector *l,
-			    struct fib_table *tb, struct notifier_block *nb)
+static void fib_leaf_notify(struct key_vector *l, struct fib_table *tb,
+			    struct notifier_block *nb)
 {
 	struct fib_alias *fa;
 
@@ -2032,20 +2032,19 @@ static void fib_leaf_notify(struct net *net, struct key_vector *l,
 		if (tb->tb_id != fa->tb_id)
 			continue;
 
-		call_fib_entry_notifier(nb, net, FIB_EVENT_ENTRY_ADD, l->key,
+		call_fib_entry_notifier(nb, FIB_EVENT_ENTRY_ADD, l->key,
 					KEYLENGTH - fa->fa_slen, fa);
 	}
 }
 
-static void fib_table_notify(struct net *net, struct fib_table *tb,
-			     struct notifier_block *nb)
+static void fib_table_notify(struct fib_table *tb, struct notifier_block *nb)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
 	struct key_vector *l, *tp = t->kv;
 	t_key key = 0;
 
 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
-		fib_leaf_notify(net, l, tb, nb);
+		fib_leaf_notify(l, tb, nb);
 
 		key = l->key + 1;
 		/* stop in case of wrap around */
@@ -2063,7 +2062,7 @@ void fib_notify(struct net *net, struct notifier_block *nb)
 		struct fib_table *tb;
 
 		hlist_for_each_entry_rcu(tb, head, tb_hlist)
-			fib_table_notify(net, tb, nb);
+			fib_table_notify(tb, nb);
 	}
 }
 
diff --git a/net/ipv4/ipmr_base.c b/net/ipv4/ipmr_base.c
index ea48bd15a575..4dcc3214e3cc 100644
--- a/net/ipv4/ipmr_base.c
+++ b/net/ipv4/ipmr_base.c
@@ -409,7 +409,7 @@ int mr_dump(struct net *net, struct notifier_block *nb, unsigned short family,
 			if (!v->dev)
 				continue;
 
-			mr_call_vif_notifier(nb, net, family,
+			mr_call_vif_notifier(nb, family,
 					     FIB_EVENT_VIF_ADD,
 					     v, vifi, mrt->id);
 		}
@@ -417,7 +417,7 @@ int mr_dump(struct net *net, struct notifier_block *nb, unsigned short family,
 
 		/* Notify on table MFC entries */
 		list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
-			mr_call_mfc_notifier(nb, net, family,
+			mr_call_mfc_notifier(nb, family,
 					     FIB_EVENT_ENTRY_ADD,
 					     mfc, mrt->id);
 	}
diff --git a/net/ipv6/fib6_notifier.c b/net/ipv6/fib6_notifier.c
index 05f82baaa99e..4fe79296999a 100644
--- a/net/ipv6/fib6_notifier.c
+++ b/net/ipv6/fib6_notifier.c
@@ -7,12 +7,12 @@
 #include <net/netns/ipv6.h>
 #include <net/ip6_fib.h>
 
-int call_fib6_notifier(struct notifier_block *nb, struct net *net,
+int call_fib6_notifier(struct notifier_block *nb,
 		       enum fib_event_type event_type,
 		       struct fib_notifier_info *info)
 {
 	info->family = AF_INET6;
-	return call_fib_notifier(nb, net, event_type, info);
+	return call_fib_notifier(nb, event_type, info);
 }
 
 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 6e2af411cd9c..f6fae48b2e18 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -357,7 +357,7 @@ unsigned int fib6_tables_seq_read(struct net *net)
 	return fib_seq;
 }
 
-static int call_fib6_entry_notifier(struct notifier_block *nb, struct net *net,
+static int call_fib6_entry_notifier(struct notifier_block *nb,
 				    enum fib_event_type event_type,
 				    struct fib6_info *rt)
 {
@@ -365,7 +365,7 @@ static int call_fib6_entry_notifier(struct notifier_block *nb, struct net *net,
 		.rt = rt,
 	};
 
-	return call_fib6_notifier(nb, net, event_type, &info.info);
+	return call_fib6_notifier(nb, event_type, &info.info);
 }
 
 int call_fib6_entry_notifiers(struct net *net,
@@ -407,7 +407,7 @@ static void fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
 {
 	if (rt == arg->net->ipv6.fib6_null_entry)
 		return;
-	call_fib6_entry_notifier(arg->nb, arg->net, FIB_EVENT_ENTRY_ADD, rt);
+	call_fib6_entry_notifier(arg->nb, FIB_EVENT_ENTRY_ADD, rt);
 }
 
 static int fib6_node_dump(struct fib6_walker *w)