net: fib_notifier: propagate possible error during fib notifier registration

Unlike events for registered notifier, during the registration, the
errors that happened for the block being registered are not propagated
up to the caller. Make sure the error is propagated for FIB rules and
entries.

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

3 files changed, 38 insertions, 19 deletions

diff --git a/net/ipv4/fib_notifier.c b/net/ipv4/fib_notifier.c
index 1a128c1346fb..0c57f68a9340 100644
--- a/net/ipv4/fib_notifier.c
+++ b/net/ipv4/fib_notifier.c
@@ -42,9 +42,7 @@ static int fib4_dump(struct net *net, struct notifier_block *nb)
 	if (err)
 		return err;
 
-	fib_notify(net, nb);
-
-	return 0;
+	return fib_notify(net, nb);
 }
 
 static const struct fib_notifier_ops fib4_notifier_ops_template = {
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 5b600b2a2aa3..568e59423773 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2015,10 +2015,11 @@ void fib_info_notify_update(struct net *net, struct nl_info *info)
 	}
 }
 
-static void fib_leaf_notify(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 fib_alias *fa;
+	int err;
 
 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
 		struct fib_info *fi = fa->fa_info;
@@ -2032,38 +2033,50 @@ static void fib_leaf_notify(struct key_vector *l, struct fib_table *tb,
 		if (tb->tb_id != fa->tb_id)
 			continue;
 
-		call_fib_entry_notifier(nb, 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);
+		if (err)
+			return err;
 	}
+	return 0;
 }
 
-static void fib_table_notify(struct fib_table *tb, struct notifier_block *nb)
+static int 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;
+	int err;
 
 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
-		fib_leaf_notify(l, tb, nb);
+		err = fib_leaf_notify(l, tb, nb);
+		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)
 {
 	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(tb, nb);
+		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
+			err = fib_table_notify(tb, nb);
+			if (err)
+				return err;
+		}
 	}
+	return 0;
 }
 
 static void __trie_free_rcu(struct rcu_head *head)
diff --git a/net/ipv4/ipmr_base.c b/net/ipv4/ipmr_base.c
index 4dcc3214e3cc..c4e23c2a0d5c 100644
--- a/net/ipv4/ipmr_base.c
+++ b/net/ipv4/ipmr_base.c
@@ -409,17 +409,25 @@ int mr_dump(struct net *net, struct notifier_block *nb, unsigned short family,
 			if (!v->dev)
 				continue;
 
-			mr_call_vif_notifier(nb, family,
-					     FIB_EVENT_VIF_ADD,
-					     v, vifi, mrt->id);
+			err = mr_call_vif_notifier(nb, family,
+						   FIB_EVENT_VIF_ADD,
+						   v, vifi, mrt->id);
+			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, 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);
+			if (err)
+				return err;
+		}
 	}
 
 	return 0;