[NET] NETNS: Omit seq_net_private->net without CONFIG_NET_NS.

Without CONFIG_NET_NS, no namespace other than &init_net exists,
no need to store net in seq_net_private.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index ce6cb34..9e491e7 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2279,9 +2279,10 @@
 	.release = fib_triestat_seq_release,
 };
 
-static struct node *fib_trie_get_idx(struct fib_trie_iter *iter, loff_t pos)
+static struct node *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
 {
-	struct net *net = iter->p.net;
+	struct fib_trie_iter *iter = seq->private;
+	struct net *net = seq_file_net(seq);
 	loff_t idx = 0;
 	unsigned int h;
 
@@ -2309,16 +2310,14 @@
 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
 	__acquires(RCU)
 {
-	struct fib_trie_iter *iter = seq->private;
-
 	rcu_read_lock();
-	return fib_trie_get_idx(iter, *pos);
+	return fib_trie_get_idx(seq, *pos);
 }
 
 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
 	struct fib_trie_iter *iter = seq->private;
-	struct net *net = iter->p.net;
+	struct net *net = seq_file_net(seq);
 	struct fib_table *tb = iter->tb;
 	struct hlist_node *tb_node;
 	unsigned int h;
@@ -2513,7 +2512,7 @@
 	struct fib_table *tb;
 
 	rcu_read_lock();
-	tb = fib_get_table(iter->p.net, RT_TABLE_MAIN);
+	tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
 	if (!tb)
 		return NULL;