fib_trie: Add slen to fib alias

Make use of an empty spot in the alias to store the suffix length so that
we don't need to pull that information from the leaf_info structure.

This patch also makes a slight change to the user statistics.  Instead of
incrementing semantic_match_miss once per leaf_info miss we now just
increment it once per leaf if a match was not found.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/fib_lookup.h

@@ -11,6 +11,7 @@ struct fib_alias {
 	u8			fa_tos;
 	u8			fa_type;
 	u8			fa_state;
+	u8			fa_slen;
 	struct rcu_head		rcu;
 };
 

net/ipv4/fib_trie.c

@@ -1219,6 +1219,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 			new_fa->fa_type = cfg->fc_type;
 			state = fa->fa_state;
 			new_fa->fa_state = state & ~FA_S_ACCESSED;
+			new_fa->fa_slen = fa->fa_slen;
 
 			hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
 			alias_free_mem_rcu(fa);
@@ -1254,10 +1255,9 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 	new_fa->fa_tos = tos;
 	new_fa->fa_type = cfg->fc_type;
 	new_fa->fa_state = 0;
-	/*
-	 * Insert new entry to the list.
-	 */
+	new_fa->fa_slen = KEYLENGTH - plen;
 
+	/* Insert new entry to the list. */
 	if (!fa_head) {
 		fa_head = fib_insert_node(t, key, plen);
 		if (unlikely(!fa_head)) {
@@ -1420,14 +1420,14 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 	hlist_for_each_entry_rcu(li, &n->list, hlist) {
 		struct fib_alias *fa;
 
-		if (((key ^ n->key) >= (1ul << li->slen)) &&
-		    ((BITS_PER_LONG > KEYLENGTH) || (li->slen != KEYLENGTH)))
-			continue;
-
 		hlist_for_each_entry_rcu(fa, &li->falh, fa_list) {
 			struct fib_info *fi = fa->fa_info;
 			int nhsel, err;
 
+			if (((key ^ n->key) >= (1ul << fa->fa_slen)) &&
+			    ((BITS_PER_LONG > KEYLENGTH) ||
+			     (fa->fa_slen != KEYLENGTH)))
+				continue;
 			if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
 				continue;
 			if (fi->fib_dead)
@@ -1455,7 +1455,7 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 				if (!(fib_flags & FIB_LOOKUP_NOREF))
 					atomic_inc(&fi->fib_clntref);
 
-				res->prefixlen = KEYLENGTH - li->slen;
+				res->prefixlen = KEYLENGTH - fa->fa_slen;
 				res->nh_sel = nhsel;
 				res->type = fa->fa_type;
 				res->scope = fi->fib_scope;
@@ -1468,11 +1468,10 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 				return err;
 			}
 		}
-
+	}
 #ifdef CONFIG_IP_FIB_TRIE_STATS
-		this_cpu_inc(stats->semantic_match_miss);
+	this_cpu_inc(stats->semantic_match_miss);
 #endif
-	}
 	goto backtrace;
 }
 EXPORT_SYMBOL_GPL(fib_table_lookup);
@@ -1735,7 +1734,7 @@ void fib_free_table(struct fib_table *tb)
 	kfree(tb);
 }
 
-static int fn_trie_dump_fa(t_key key, int slen, struct hlist_head *fah,
+static int fn_trie_dump_fa(t_key key, struct hlist_head *fah,
 			   struct fib_table *tb,
 			   struct sk_buff *skb, struct netlink_callback *cb)
 {
@@ -1760,7 +1759,7 @@ static int fn_trie_dump_fa(t_key key, int slen, struct hlist_head *fah,
 				  tb->tb_id,
 				  fa->fa_type,
 				  xkey,
-				  KEYLENGTH - slen,
+				  KEYLENGTH - fa->fa_slen,
 				  fa->fa_tos,
 				  fa->fa_info, NLM_F_MULTI) < 0) {
 			cb->args[5] = i;
@@ -1794,7 +1793,7 @@ static int fn_trie_dump_leaf(struct tnode *l, struct fib_table *tb,
 		if (hlist_empty(&li->falh))
 			continue;
 
-		if (fn_trie_dump_fa(l->key, li->slen, &li->falh, tb, skb, cb) < 0) {
+		if (fn_trie_dump_fa(l->key, &li->falh, tb, skb, cb) < 0) {
 			cb->args[4] = i;
 			return -1;
 		}
@@ -2281,7 +2280,7 @@ static int fib_trie_seq_show(struct seq_file *seq, void *v)
 
 				seq_indent(seq, iter->depth+1);
 				seq_printf(seq, "  /%zu %s %s",
-					   KEYLENGTH - li->slen,
+					   KEYLENGTH - fa->fa_slen,
 					   rtn_scope(buf1, sizeof(buf1),
 						     fa->fa_info->fib_scope),
 					   rtn_type(buf2, sizeof(buf2),
@@ -2419,6 +2418,7 @@ static int fib_route_seq_show(struct seq_file *seq, void *v)
 {
 	struct tnode *l = v;
 	struct leaf_info *li;
+	__be32 prefix;
 
 	if (v == SEQ_START_TOKEN) {
 		seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
@@ -2427,15 +2427,14 @@ static int fib_route_seq_show(struct seq_file *seq, void *v)
 		return 0;
 	}
 
+	prefix = htonl(l->key);
+
 	hlist_for_each_entry_rcu(li, &l->list, hlist) {
 		struct fib_alias *fa;
-		__be32 mask, prefix;
-
-		mask = inet_make_mask(KEYLENGTH - li->slen);
-		prefix = htonl(l->key);
 
 		hlist_for_each_entry_rcu(fa, &li->falh, fa_list) {
 			const struct fib_info *fi = fa->fa_info;
+			__be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
 			unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
 
 			if (fa->fa_type == RTN_BROADCAST