ipv4: Avoid overhead when no custom FIB rules are installed.

If the user hasn't actually installed any custom rules, or fiddled
with the default ones, don't go through the whole FIB rules layer.

It's just pure overhead.

Instead do what we do with CONFIG_IP_MULTIPLE_TABLES disabled, check
the individual tables by hand, one by one.

Also, move fib_num_tclassid_users into the ipv4 network namespace.

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

1 files changed, 8 insertions, 4 deletions

diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index b23fd952c84f..c06da93b0b70 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -54,7 +54,7 @@ u32 fib_rules_tclass(const struct fib_result *res)
 }
 #endif
 
-int fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res)
+int __fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res)
 {
         struct fib_lookup_arg arg = {
                 .result = res,
@@ -67,7 +67,7 @@ int fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res)
 
         return err;
 }
-EXPORT_SYMBOL_GPL(fib_lookup);
+EXPORT_SYMBOL_GPL(__fib_lookup);
 
 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
                             int flags, struct fib_lookup_arg *arg)
@@ -172,7 +172,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
         if (tb[FRA_FLOW]) {
                 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
                 if (rule4->tclassid)
-                        fib_num_tclassid_users++;
+                        net->ipv4.fib_num_tclassid_users++;
         }
 #endif
 
@@ -182,6 +182,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
         rule4->dstmask = inet_make_mask(rule4->dst_len);
         rule4->tos = frh->tos;
 
+        net->ipv4.fib_has_custom_rules = true;
         err = 0;
 errout:
         return err;
@@ -189,12 +190,14 @@ errout:
 
 static void fib4_rule_delete(struct fib_rule *rule)
 {
+        struct net *net = rule->fr_net;
 #ifdef CONFIG_IP_ROUTE_CLASSID
         struct fib4_rule *rule4 = (struct fib4_rule *) rule;
 
         if (rule4->tclassid)
-                fib_num_tclassid_users--;
+                net->ipv4.fib_num_tclassid_users--;
 #endif
+        net->ipv4.fib_has_custom_rules = true;
 }
 
 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
@@ -309,6 +312,7 @@ int __net_init fib4_rules_init(struct net *net)
         if (err < 0)
                 goto fail;
         net->ipv4.rules_ops = ops;
+        net->ipv4.fib_has_custom_rules = false;
         return 0;
 
 fail: