ipv6: prevent fib6_run_gc() contention

[pandora-kernel.git] / net / ipv6 / ip6_fib.c

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 93718f3..ddedf63 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -862,14 +862,22 @@ static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
 
                        if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
 #ifdef CONFIG_IPV6_SUBTREES
-                               if (fn->subtree)
-                                       fn = fib6_lookup_1(fn->subtree, args + 1);
+                               if (fn->subtree) {
+                                       struct fib6_node *sfn;
+                                       sfn = fib6_lookup_1(fn->subtree,
+                                                           args + 1);
+                                       if (!sfn)
+                                               goto backtrack;
+                                       fn = sfn;
+                               }
 #endif
-                               if (!fn || fn->fn_flags & RTN_RTINFO)
+                               if (fn->fn_flags & RTN_RTINFO)
                                        return fn;
                        }
                }
-
+#ifdef CONFIG_IPV6_SUBTREES
+backtrack:
+#endif
                if (fn->fn_flags & RTN_ROOT)
                        break;
 
@@ -1268,9 +1276,9 @@ static int fib6_walk_continue(struct fib6_walker_t *w)
                        if (w->leaf && fn->fn_flags&RTN_RTINFO) {
                                int err;
 
-                               if (w->count < w->skip) {
-                                       w->count++;
-                                       continue;
+                               if (w->skip) {
+                                       w->skip--;
+                                       goto skip;
                                }
 
                                err = w->func(w);
@@ -1280,6 +1288,7 @@ static int fib6_walk_continue(struct fib6_walker_t *w)
                                w->count++;
                                continue;
                        }
+skip:
                        w->state = FWS_U;
                case FWS_U:
                        if (fn == w->root)
@@ -1464,19 +1473,16 @@ static int fib6_age(struct rt6_info *rt, void *arg)
 
 static DEFINE_SPINLOCK(fib6_gc_lock);
 
-void fib6_run_gc(unsigned long expires, struct net *net)
+void fib6_run_gc(unsigned long expires, struct net *net, bool force)
 {
-       if (expires != ~0UL) {
+       if (force) {
                spin_lock_bh(&fib6_gc_lock);
-               gc_args.timeout = expires ? (int)expires :
-                       net->ipv6.sysctl.ip6_rt_gc_interval;
-       } else {
-               if (!spin_trylock_bh(&fib6_gc_lock)) {
-                       mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
-                       return;
-               }
-               gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
+       } else if (!spin_trylock_bh(&fib6_gc_lock)) {
+               mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
+               return;
        }
+       gc_args.timeout = expires ? (int)expires :
+                         net->ipv6.sysctl.ip6_rt_gc_interval;
 
        gc_args.more = icmp6_dst_gc();
 
@@ -1493,7 +1499,7 @@ void fib6_run_gc(unsigned long expires, struct net *net)
 
 static void fib6_gc_timer_cb(unsigned long arg)
 {
-       fib6_run_gc(0, (struct net *)arg);
+       fib6_run_gc(0, (struct net *)arg, true);
 }
 
 static int __net_init fib6_net_init(struct net *net)