Merge branch 'devlink-allow-devlink-instances-to-change-network-namespace'

Jiri Pirko says:

====================
devlink: allow devlink instances to change network namespace

Devlink from the beginning counts with network namespaces, but the
instances has been fixed to init_net.

Implement change of network namespace as part of "devlink reload"
procedure like this:

$ ip netns add testns1
$ devlink/devlink dev reload netdevsim/netdevsim10 netns testns1

This command reloads device "netdevsim10" into network
namespace "testns1".

Note that "devlink reload" reinstantiates driver objects, effectively it
reloads the driver instance, including possible hw reset etc. Newly
created netdevices respect the network namespace of the parent devlink
instance and according to that, they are created in target network
namespace.

Driver is able to refuse to be reloaded into different namespace. That
is the case of mlx4 right now.

FIB entries and rules are replayed during FIB notifier registration
which is triggered during reload (driver instance init). FIB notifier
is also registered to the target network namespace, that allows user
to use netdevsim devlink resources to setup per-namespace limits of FIB
entries and FIB rules. In fact, with multiple netdevsim instances
in each network namespace, user might setup different limits.
This maintains and extends current netdevsim resources behaviour.

Patch 1 prepares netdevsim code for the follow-up changes in the
patchset. It does not change the behaviour, only moves pet-init_netns
accounting to netdevsim instance, which is also in init_netns.

Patches 2-5 prepare the FIB notifier making it per-netns and to behave
correctly upon error conditions.

Patch 6 just exports a devlink_net helper so it can be used in drivers.

Patches 7-9 do preparations in mlxsw driver.

Patches 10-13 do preparations in netdevsim driver, namely patch 12
implements proper devlink reload where the driver instance objects are
actually re-created as they should be.

Patch 14 actually implements the possibility to reload into a different
network namespace.

Patch 15 adds needed selftests for devlink reload into namespace for
netdevsim driver.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

12 files changed, 326 insertions, 133 deletions

diff --git a/net/core/devlink.c b/net/core/devlink.c
index e48680efe54a..c4d8c4ab0fb5 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -95,10 +95,11 @@ static LIST_HEAD(devlink_list);
  */
 static DEFINE_MUTEX(devlink_mutex);
 
-static struct net *devlink_net(const struct devlink *devlink)
+struct net *devlink_net(const struct devlink *devlink)
 {
 	return read_pnet(&devlink->_net);
 }
+EXPORT_SYMBOL_GPL(devlink_net);
 
 static void devlink_net_set(struct devlink *devlink, struct net *net)
 {
@@ -434,8 +435,16 @@ static void devlink_nl_post_doit(const struct genl_ops *ops,
 {
 	struct devlink *devlink;
 
-	devlink = devlink_get_from_info(info);
-	if (~ops->internal_flags & DEVLINK_NL_FLAG_NO_LOCK)
+	/* When devlink changes netns, it would not be found
+	 * by devlink_get_from_info(). So try if it is stored first.
+	 */
+	if (ops->internal_flags & DEVLINK_NL_FLAG_NEED_DEVLINK) {
+		devlink = info->user_ptr[0];
+	} else {
+		devlink = devlink_get_from_info(info);
+		WARN_ON(IS_ERR(devlink));
+	}
+	if (!IS_ERR(devlink) && ~ops->internal_flags & DEVLINK_NL_FLAG_NO_LOCK)
 		mutex_unlock(&devlink->lock);
 	mutex_unlock(&devlink_mutex);
 }
@@ -2674,6 +2683,72 @@ devlink_resources_validate(struct devlink *devlink,
 	return err;
 }
 
+static struct net *devlink_netns_get(struct sk_buff *skb,
+				     struct genl_info *info)
+{
+	struct nlattr *netns_pid_attr = info->attrs[DEVLINK_ATTR_NETNS_PID];
+	struct nlattr *netns_fd_attr = info->attrs[DEVLINK_ATTR_NETNS_FD];
+	struct nlattr *netns_id_attr = info->attrs[DEVLINK_ATTR_NETNS_ID];
+	struct net *net;
+
+	if (!!netns_pid_attr + !!netns_fd_attr + !!netns_id_attr > 1) {
+		NL_SET_ERR_MSG(info->extack, "multiple netns identifying attributes specified");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (netns_pid_attr) {
+		net = get_net_ns_by_pid(nla_get_u32(netns_pid_attr));
+	} else if (netns_fd_attr) {
+		net = get_net_ns_by_fd(nla_get_u32(netns_fd_attr));
+	} else if (netns_id_attr) {
+		net = get_net_ns_by_id(sock_net(skb->sk),
+				       nla_get_u32(netns_id_attr));
+		if (!net)
+			net = ERR_PTR(-EINVAL);
+	} else {
+		WARN_ON(1);
+		net = ERR_PTR(-EINVAL);
+	}
+	if (IS_ERR(net)) {
+		NL_SET_ERR_MSG(info->extack, "Unknown network namespace");
+		return ERR_PTR(-EINVAL);
+	}
+	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) {
+		put_net(net);
+		return ERR_PTR(-EPERM);
+	}
+	return net;
+}
+
+static void devlink_param_notify(struct devlink *devlink,
+				 unsigned int port_index,
+				 struct devlink_param_item *param_item,
+				 enum devlink_command cmd);
+
+static void devlink_reload_netns_change(struct devlink *devlink,
+					struct net *dest_net)
+{
+	struct devlink_param_item *param_item;
+
+	/* Userspace needs to be notified about devlink objects
+	 * removed from original and entering new network namespace.
+	 * The rest of the devlink objects are re-created during
+	 * reload process so the notifications are generated separatelly.
+	 */
+
+	list_for_each_entry(param_item, &devlink->param_list, list)
+		devlink_param_notify(devlink, 0, param_item,
+				     DEVLINK_CMD_PARAM_DEL);
+	devlink_notify(devlink, DEVLINK_CMD_DEL);
+
+	devlink_net_set(devlink, dest_net);
+
+	devlink_notify(devlink, DEVLINK_CMD_NEW);
+	list_for_each_entry(param_item, &devlink->param_list, list)
+		devlink_param_notify(devlink, 0, param_item,
+				     DEVLINK_CMD_PARAM_NEW);
+}
+
 static bool devlink_reload_supported(struct devlink *devlink)
 {
 	return devlink->ops->reload_down && devlink->ops->reload_up;
@@ -2694,9 +2769,27 @@ bool devlink_is_reload_failed(const struct devlink *devlink)
 }
 EXPORT_SYMBOL_GPL(devlink_is_reload_failed);
 
+static int devlink_reload(struct devlink *devlink, struct net *dest_net,
+			  struct netlink_ext_ack *extack)
+{
+	int err;
+
+	err = devlink->ops->reload_down(devlink, !!dest_net, extack);
+	if (err)
+		return err;
+
+	if (dest_net && !net_eq(dest_net, devlink_net(devlink)))
+		devlink_reload_netns_change(devlink, dest_net);
+
+	err = devlink->ops->reload_up(devlink, extack);
+	devlink_reload_failed_set(devlink, !!err);
+	return err;
+}
+
 static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
 {
 	struct devlink *devlink = info->user_ptr[0];
+	struct net *dest_net = NULL;
 	int err;
 
 	if (!devlink_reload_supported(devlink))
@@ -2707,11 +2800,20 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
 		NL_SET_ERR_MSG_MOD(info->extack, "resources size validation failed");
 		return err;
 	}
-	err = devlink->ops->reload_down(devlink, info->extack);
-	if (err)
-		return err;
-	err = devlink->ops->reload_up(devlink, info->extack);
-	devlink_reload_failed_set(devlink, !!err);
+
+	if (info->attrs[DEVLINK_ATTR_NETNS_PID] ||
+	    info->attrs[DEVLINK_ATTR_NETNS_FD] ||
+	    info->attrs[DEVLINK_ATTR_NETNS_ID]) {
+		dest_net = devlink_netns_get(skb, info);
+		if (IS_ERR(dest_net))
+			return PTR_ERR(dest_net);
+	}
+
+	err = devlink_reload(devlink, dest_net, info->extack);
+
+	if (dest_net)
+		put_net(dest_net);
+
 	return err;
 }
 
@@ -5793,6 +5895,9 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_TRAP_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_TRAP_ACTION] = { .type = NLA_U8 },
 	[DEVLINK_ATTR_TRAP_GROUP_NAME] = { .type = NLA_NUL_STRING },
+	[DEVLINK_ATTR_NETNS_PID] = { .type = NLA_U32 },
+	[DEVLINK_ATTR_NETNS_FD] = { .type = NLA_U32 },
+	[DEVLINK_ATTR_NETNS_ID] = { .type = NLA_U32 },
 };
 
 static const struct genl_ops devlink_nl_ops[] = {
@@ -8060,9 +8165,43 @@ int devlink_compat_switch_id_get(struct net_device *dev,
 	return 0;
 }
 
+static void __net_exit devlink_pernet_pre_exit(struct net *net)
+{
+	struct devlink *devlink;
+	int err;
+
+	/* In case network namespace is getting destroyed, reload
+	 * all devlink instances from this namespace into init_net.
+	 */
+	mutex_lock(&devlink_mutex);
+	list_for_each_entry(devlink, &devlink_list, list) {
+		if (net_eq(devlink_net(devlink), net)) {
+			if (WARN_ON(!devlink_reload_supported(devlink)))
+				continue;
+			err = devlink_reload(devlink, &init_net, NULL);
+			if (err)
+				pr_warn("Failed to reload devlink instance into init_net\n");
+		}
+	}
+	mutex_unlock(&devlink_mutex);
+}
+
+static struct pernet_operations devlink_pernet_ops __net_initdata = {
+	.pre_exit = devlink_pernet_pre_exit,
+};
+
 static int __init devlink_init(void)
 {
-	return genl_register_family(&devlink_nl_family);
+	int err;
+
+	err = genl_register_family(&devlink_nl_family);
+	if (err)
+		goto out;
+	err = register_pernet_subsys(&devlink_pernet_ops);
+
+out:
+	WARN_ON(err);
+	return err;
 }
 
 subsys_initcall(devlink_init);
diff --git a/net/core/fib_notifier.c b/net/core/fib_notifier.c
index 470a606d5e8d..fc96259807b6 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);
 }
@@ -31,106 +29,100 @@ 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;
 }
 
-static int fib_net_dump(struct net *net, struct notifier_block *nb)
+static int fib_net_dump(struct net *net, struct notifier_block *nb,
+			struct netlink_ext_ack *extack)
 {
 	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);
+		err = ops->fib_dump(net, nb, extack);
 		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,
-			  void (*cb)(struct notifier_block *nb))
+int register_fib_notifier(struct net *net, struct notifier_block *nb,
+			  void (*cb)(struct notifier_block *nb),
+			  struct netlink_ext_ack *extack)
 {
 	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, extack);
+		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 +173,7 @@ 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..3e7e15278c46 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -321,16 +321,18 @@ 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)
+				  struct fib_rule *rule, int family,
+				  struct netlink_ext_ack *extack)
 {
 	struct fib_rule_notifier_info info = {
 		.info.family = family,
+		.info.extack = extack,
 		.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,
@@ -350,20 +352,25 @@ static int call_fib_rule_notifiers(struct net *net,
 }
 
 /* Called with rcu_read_lock() */
-int fib_rules_dump(struct net *net, struct notifier_block *nb, int family)
+int fib_rules_dump(struct net *net, struct notifier_block *nb, int family,
+		   struct netlink_ext_ack *extack)
 {
 	struct fib_rules_ops *ops;
 	struct fib_rule *rule;
+	int err = 0;
 
 	ops = lookup_rules_ops(net, 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);
+	list_for_each_entry_rcu(rule, &ops->rules_list, list) {
+		err = call_fib_rule_notifier(nb, FIB_EVENT_RULE_ADD,
+					     rule, family, extack);
+		if (err)
+			break;
+	}
 	rules_ops_put(ops);
 
-	return 0;
+	return err;
 }
 EXPORT_SYMBOL_GPL(fib_rules_dump);
 
diff --git a/net/ipv4/fib_notifier.c b/net/ipv4/fib_notifier.c
index b804ccbdb241..0c28bd469a68 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,
@@ -34,17 +34,16 @@ static unsigned int fib4_seq_read(struct net *net)
 	return net->ipv4.fib_seq + fib4_rules_seq_read(net);
 }
 
-static int fib4_dump(struct net *net, struct notifier_block *nb)
+static int fib4_dump(struct net *net, struct notifier_block *nb,
+		     struct netlink_ext_ack *extack)
 {
 	int err;
 
-	err = fib4_rules_dump(net, nb);
+	err = fib4_rules_dump(net, nb, extack);
 	if (err)
 		return err;
 
-	fib_notify(net, nb);
-
-	return 0;
+	return fib_notify(net, nb, extack);
 }
 
 static const struct fib_notifier_ops fib4_notifier_ops_template = {
diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index b43a7ba5c6a4..f99e3bac5cab 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -65,9 +65,10 @@ bool fib4_rule_default(const struct fib_rule *rule)
 }
 EXPORT_SYMBOL_GPL(fib4_rule_default);
 
-int fib4_rules_dump(struct net *net, struct notifier_block *nb)
+int fib4_rules_dump(struct net *net, struct notifier_block *nb,
+		    struct netlink_ext_ack *extack)
 {
-	return fib_rules_dump(net, nb, AF_INET);
+	return fib_rules_dump(net, nb, AF_INET, extack);
 }
 
 unsigned int fib4_rules_seq_read(struct net *net)
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 1ab2fb6bb37d..b9df9c09b84e 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -74,11 +74,13 @@
 #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)
+				   int dst_len, struct fib_alias *fa,
+				   struct netlink_ext_ack *extack)
 {
 	struct fib_entry_notifier_info info = {
+		.info.extack = extack,
 		.dst = dst,
 		.dst_len = dst_len,
 		.fi = fa->fa_info,
@@ -86,7 +88,7 @@ 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,
@@ -2015,10 +2017,12 @@ 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 int fib_leaf_notify(struct key_vector *l, struct fib_table *tb,
+			   struct notifier_block *nb,
+			   struct netlink_ext_ack *extack)
 {
 	struct fib_alias *fa;
+	int err;
 
 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
 		struct fib_info *fi = fa->fa_info;
@@ -2032,39 +2036,53 @@ 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,
-					KEYLENGTH - fa->fa_slen, fa);
+		err = call_fib_entry_notifier(nb, FIB_EVENT_ENTRY_ADD, l->key,
+					      KEYLENGTH - fa->fa_slen,
+					      fa, extack);
+		if (err)
+			return err;
 	}
+	return 0;
 }
 
-static void fib_table_notify(struct net *net, struct fib_table *tb,
-			     struct notifier_block *nb)
+static int fib_table_notify(struct fib_table *tb, struct notifier_block *nb,
+			    struct netlink_ext_ack *extack)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
 	struct key_vector *l, *tp = t->kv;
 	t_key key = 0;
+	int err;
 
 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
-		fib_leaf_notify(net, l, tb, nb);
+		err = fib_leaf_notify(l, tb, nb, extack);
+		if (err)
+			return err;
 
 		key = l->key + 1;
 		/* stop in case of wrap around */
 		if (key < l->key)
 			break;
 	}
+	return 0;
 }
 
-void fib_notify(struct net *net, struct notifier_block *nb)
+int fib_notify(struct net *net, struct notifier_block *nb,
+	       struct netlink_ext_ack *extack)
 {
 	unsigned int h;
+	int err;
 
 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
 		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
 		struct fib_table *tb;
 
-		hlist_for_each_entry_rcu(tb, head, tb_hlist)
-			fib_table_notify(net, tb, nb);
+		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
+			err = fib_table_notify(tb, nb, extack);
+			if (err)
+				return err;
+		}
 	}
+	return 0;
 }
 
 static void __trie_free_rcu(struct rcu_head *head)
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 313470f6bb14..051f365b64d2 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -278,9 +278,10 @@ static void __net_exit ipmr_rules_exit(struct net *net)
 	rtnl_unlock();
 }
 
-static int ipmr_rules_dump(struct net *net, struct notifier_block *nb)
+static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
+			   struct netlink_ext_ack *extack)
 {
-	return fib_rules_dump(net, nb, RTNL_FAMILY_IPMR);
+	return fib_rules_dump(net, nb, RTNL_FAMILY_IPMR, extack);
 }
 
 static unsigned int ipmr_rules_seq_read(struct net *net)
@@ -336,7 +337,8 @@ static void __net_exit ipmr_rules_exit(struct net *net)
 	rtnl_unlock();
 }
 
-static int ipmr_rules_dump(struct net *net, struct notifier_block *nb)
+static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
+			   struct netlink_ext_ack *extack)
 {
 	return 0;
 }
@@ -3040,10 +3042,11 @@ static unsigned int ipmr_seq_read(struct net *net)
 	return net->ipv4.ipmr_seq + ipmr_rules_seq_read(net);
 }
 
-static int ipmr_dump(struct net *net, struct notifier_block *nb)
+static int ipmr_dump(struct net *net, struct notifier_block *nb,
+		     struct netlink_ext_ack *extack)
 {
 	return mr_dump(net, nb, RTNL_FAMILY_IPMR, ipmr_rules_dump,
-		       ipmr_mr_table_iter, &mrt_lock);
+		       ipmr_mr_table_iter, &mrt_lock, extack);
 }
 
 static const struct fib_notifier_ops ipmr_notifier_ops_template = {
diff --git a/net/ipv4/ipmr_base.c b/net/ipv4/ipmr_base.c
index ea48bd15a575..aa8738a91210 100644
--- a/net/ipv4/ipmr_base.c
+++ b/net/ipv4/ipmr_base.c
@@ -386,15 +386,17 @@ EXPORT_SYMBOL(mr_rtm_dumproute);
 
 int mr_dump(struct net *net, struct notifier_block *nb, unsigned short family,
 	    int (*rules_dump)(struct net *net,
-			      struct notifier_block *nb),
+			      struct notifier_block *nb,
+			      struct netlink_ext_ack *extack),
 	    struct mr_table *(*mr_iter)(struct net *net,
 					struct mr_table *mrt),
-	    rwlock_t *mrt_lock)
+	    rwlock_t *mrt_lock,
+	    struct netlink_ext_ack *extack)
 {
 	struct mr_table *mrt;
 	int err;
 
-	err = rules_dump(net, nb);
+	err = rules_dump(net, nb, extack);
 	if (err)
 		return err;
 
@@ -409,17 +411,25 @@ int mr_dump(struct net *net, struct notifier_block *nb, unsigned short family,
 			if (!v->dev)
 				continue;
 
-			mr_call_vif_notifier(nb, net, family,
-					     FIB_EVENT_VIF_ADD,
-					     v, vifi, mrt->id);
+			err = mr_call_vif_notifier(nb, family,
+						   FIB_EVENT_VIF_ADD,
+						   v, vifi, mrt->id, extack);
+			if (err)
+				break;
 		}
 		read_unlock(mrt_lock);
 
+		if (err)
+			return err;
+
 		/* Notify on table MFC entries */
-		list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
-			mr_call_mfc_notifier(nb, net, family,
-					     FIB_EVENT_ENTRY_ADD,
-					     mfc, mrt->id);
+		list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list) {
+			err = mr_call_mfc_notifier(nb, family,
+						   FIB_EVENT_ENTRY_ADD,
+						   mfc, mrt->id, extack);
+			if (err)
+				return err;
+		}
 	}
 
 	return 0;
diff --git a/net/ipv6/fib6_notifier.c b/net/ipv6/fib6_notifier.c
index 05f82baaa99e..f87ae33e1d01 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,
@@ -27,15 +27,16 @@ static unsigned int fib6_seq_read(struct net *net)
 	return fib6_tables_seq_read(net) + fib6_rules_seq_read(net);
 }
 
-static int fib6_dump(struct net *net, struct notifier_block *nb)
+static int fib6_dump(struct net *net, struct notifier_block *nb,
+		     struct netlink_ext_ack *extack)
 {
 	int err;
 
-	err = fib6_rules_dump(net, nb);
+	err = fib6_rules_dump(net, nb, extack);
 	if (err)
 		return err;
 
-	return fib6_tables_dump(net, nb);
+	return fib6_tables_dump(net, nb, extack);
 }
 
 static const struct fib_notifier_ops fib6_notifier_ops_template = {
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index f9e8fe3ff0c5..fafe556d21e0 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -47,9 +47,10 @@ bool fib6_rule_default(const struct fib_rule *rule)
 }
 EXPORT_SYMBOL_GPL(fib6_rule_default);
 
-int fib6_rules_dump(struct net *net, struct notifier_block *nb)
+int fib6_rules_dump(struct net *net, struct notifier_block *nb,
+		    struct netlink_ext_ack *extack)
 {
-	return fib_rules_dump(net, nb, AF_INET6);
+	return fib_rules_dump(net, nb, AF_INET6, extack);
 }
 
 unsigned int fib6_rules_seq_read(struct net *net)
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 6e2af411cd9c..f66bc2af4e9d 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -357,15 +357,17 @@ 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)
+				    struct fib6_info *rt,
+				    struct netlink_ext_ack *extack)
 {
 	struct fib6_entry_notifier_info info = {
+		.info.extack = extack,
 		.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,
@@ -401,40 +403,51 @@ int call_fib6_multipath_entry_notifiers(struct net *net,
 struct fib6_dump_arg {
 	struct net *net;
 	struct notifier_block *nb;
+	struct netlink_ext_ack *extack;
 };
 
-static void fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
+static int 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);
+		return 0;
+	return call_fib6_entry_notifier(arg->nb, FIB_EVENT_ENTRY_ADD,
+					rt, arg->extack);
 }
 
 static int fib6_node_dump(struct fib6_walker *w)
 {
 	struct fib6_info *rt;
+	int err = 0;
 
-	for_each_fib6_walker_rt(w)
-		fib6_rt_dump(rt, w->args);
+	for_each_fib6_walker_rt(w) {
+		err = fib6_rt_dump(rt, w->args);
+		if (err)
+			break;
+	}
 	w->leaf = NULL;
-	return 0;
+	return err;
 }
 
-static void fib6_table_dump(struct net *net, struct fib6_table *tb,
-			    struct fib6_walker *w)
+static int fib6_table_dump(struct net *net, struct fib6_table *tb,
+			   struct fib6_walker *w)
 {
+	int err;
+
 	w->root = &tb->tb6_root;
 	spin_lock_bh(&tb->tb6_lock);
-	fib6_walk(net, w);
+	err = fib6_walk(net, w);
 	spin_unlock_bh(&tb->tb6_lock);
+	return err;
 }
 
 /* Called with rcu_read_lock() */
-int fib6_tables_dump(struct net *net, struct notifier_block *nb)
+int fib6_tables_dump(struct net *net, struct notifier_block *nb,
+		     struct netlink_ext_ack *extack)
 {
 	struct fib6_dump_arg arg;
 	struct fib6_walker *w;
 	unsigned int h;
+	int err = 0;
 
 	w = kzalloc(sizeof(*w), GFP_ATOMIC);
 	if (!w)
@@ -443,19 +456,24 @@ int fib6_tables_dump(struct net *net, struct notifier_block *nb)
 	w->func = fib6_node_dump;
 	arg.net = net;
 	arg.nb = nb;
+	arg.extack = extack;
 	w->args = &arg;
 
 	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
 		struct hlist_head *head = &net->ipv6.fib_table_hash[h];
 		struct fib6_table *tb;
 
-		hlist_for_each_entry_rcu(tb, head, tb6_hlist)
-			fib6_table_dump(net, tb, w);
+		hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
+			err = fib6_table_dump(net, tb, w);
+			if (err < 0)
+				goto out;
+		}
 	}
 
+out:
 	kfree(w);
 
-	return 0;
+	return err;
 }
 
 static int fib6_dump_node(struct fib6_walker *w)
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 857a89ad4d6c..bfa49ff70531 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -265,9 +265,10 @@ static void __net_exit ip6mr_rules_exit(struct net *net)
 	rtnl_unlock();
 }
 
-static int ip6mr_rules_dump(struct net *net, struct notifier_block *nb)
+static int ip6mr_rules_dump(struct net *net, struct notifier_block *nb,
+			    struct netlink_ext_ack *extack)
 {
-	return fib_rules_dump(net, nb, RTNL_FAMILY_IP6MR);
+	return fib_rules_dump(net, nb, RTNL_FAMILY_IP6MR, extack);
 }
 
 static unsigned int ip6mr_rules_seq_read(struct net *net)
@@ -324,7 +325,8 @@ static void __net_exit ip6mr_rules_exit(struct net *net)
 	rtnl_unlock();
 }
 
-static int ip6mr_rules_dump(struct net *net, struct notifier_block *nb)
+static int ip6mr_rules_dump(struct net *net, struct notifier_block *nb,
+			    struct netlink_ext_ack *extack)
 {
 	return 0;
 }
@@ -1256,10 +1258,11 @@ static unsigned int ip6mr_seq_read(struct net *net)
 	return net->ipv6.ipmr_seq + ip6mr_rules_seq_read(net);
 }
 
-static int ip6mr_dump(struct net *net, struct notifier_block *nb)
+static int ip6mr_dump(struct net *net, struct notifier_block *nb,
+		      struct netlink_ext_ack *extack)
 {
 	return mr_dump(net, nb, RTNL_FAMILY_IP6MR, ip6mr_rules_dump,
-		       ip6mr_mr_table_iter, &mrt_lock);
+		       ip6mr_mr_table_iter, &mrt_lock, extack);
 }
 
 static struct notifier_block ip6_mr_notifier = {