Patchwork [RFC(v2),net-next,13/13] ipv6: Complete neighbour entry removal from dst_entry.

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Submitter YOSHIFUJI Hideaki / 吉藤英明
Date Jan. 15, 2013, 4:46 p.m.
Message ID <50F587ED.5070602@linux-ipv6.org>
Download mbox | patch
Permalink /patch/212239/
State RFC
Delegated to: David Miller
Headers show

Comments

YOSHIFUJI Hideaki / 吉藤英明 - Jan. 15, 2013, 4:46 p.m.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
---
 include/net/ip6_fib.h   |    2 --
 net/ipv6/route.c        |   68 +++--------------------------------------------
 net/ipv6/xfrm6_policy.c |    1 -
 3 files changed, 3 insertions(+), 68 deletions(-)
WANG Cong - Jan. 16, 2013, 7:09 a.m.
On 01/16/2013 12:46 AM, YOSHIFUJI Hideaki wrote:
> +#if 0
>   		if (rt->n && rt->n->dev == dev) {
>   			rt->n->dev = loopback_dev;
>   			dev_hold(loopback_dev);
>   			dev_put(dev);
>   		}
> +#endif

Why commenting this out instead of removing it? As rt->n is totally
removed, how possible could we reuse this code in future?

Thanks.
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YOSHIFUJI Hideaki / 吉藤英明 - Jan. 16, 2013, 2:04 p.m.
Cong Wang wrote:
> On 01/16/2013 12:46 AM, YOSHIFUJI Hideaki wrote:
>> +#if 0
>>   		if (rt->n && rt->n->dev == dev) {
>>   			rt->n->dev = loopback_dev;
>>   			dev_hold(loopback_dev);
>>   			dev_put(dev);
>>   		}
>> +#endif
> 
> Why commenting this out instead of removing it? As rt->n is totally
> removed, how possible could we reuse this code in future?

I have confirmed that this dev_put()/dev_hold() operation are really
for neigh->dev, which has refcnt for dev, so I agree.

(This is why I need to revisit refcnt 

--yoshfuji
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Patch

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index fdc48a9..6919a50 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -89,8 +89,6 @@  struct fib6_table;
 struct rt6_info {
 	struct dst_entry		dst;
 
-	struct neighbour		*n;
-
 	/*
 	 * Tail elements of dst_entry (__refcnt etc.)
 	 * and these elements (rarely used in hot path) are in
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 9605658..e30177a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -151,19 +151,6 @@  static struct neighbour *ip6_neigh_lookup(const struct dst_entry *dst,
 	return neigh_create(&nd_tbl, daddr, dst->dev);
 }
 
-static int rt6_bind_neighbour(struct rt6_info *rt, struct net_device *dev)
-{
-	struct neighbour *n = __ipv6_neigh_lookup(dev, &rt->rt6i_gateway);
-	if (!n) {
-		n = neigh_create(&nd_tbl, &rt->rt6i_gateway, dev);
-		if (IS_ERR(n))
-			return PTR_ERR(n);
-	}
-	rt->n = n;
-
-	return 0;
-}
-
 static struct dst_ops ip6_dst_ops_template = {
 	.family			=	AF_INET6,
 	.protocol		=	cpu_to_be16(ETH_P_IPV6),
@@ -301,9 +288,6 @@  static void ip6_dst_destroy(struct dst_entry *dst)
 	struct rt6_info *rt = (struct rt6_info *)dst;
 	struct inet6_dev *idev = rt->rt6i_idev;
 
-	if (rt->n)
-		neigh_release(rt->n);
-
 	if (!(rt->dst.flags & DST_HOST))
 		dst_destroy_metrics_generic(dst);
 
@@ -354,11 +338,13 @@  static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 				in6_dev_put(idev);
 			}
 		}
+#if 0
 		if (rt->n && rt->n->dev == dev) {
 			rt->n->dev = loopback_dev;
 			dev_hold(loopback_dev);
 			dev_put(dev);
 		}
+#endif
 	}
 }
 
@@ -846,8 +832,6 @@  static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort,
 	rt = ip6_rt_copy(ort, daddr);
 
 	if (rt) {
-		int attempts = !in_softirq();
-
 		if (!(rt->rt6i_flags & RTF_GATEWAY)) {
 			if (ort->rt6i_dst.plen != 128 &&
 			    ipv6_addr_equal(&ort->rt6i_dst.addr, daddr))
@@ -863,32 +847,6 @@  static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort,
 			rt->rt6i_src.plen = 128;
 		}
 #endif
-
-	retry:
-		if (rt6_bind_neighbour(rt, rt->dst.dev)) {
-			struct net *net = dev_net(rt->dst.dev);
-			int saved_rt_min_interval =
-				net->ipv6.sysctl.ip6_rt_gc_min_interval;
-			int saved_rt_elasticity =
-				net->ipv6.sysctl.ip6_rt_gc_elasticity;
-
-			if (attempts-- > 0) {
-				net->ipv6.sysctl.ip6_rt_gc_elasticity = 1;
-				net->ipv6.sysctl.ip6_rt_gc_min_interval = 0;
-
-				ip6_dst_gc(&net->ipv6.ip6_dst_ops);
-
-				net->ipv6.sysctl.ip6_rt_gc_elasticity =
-					saved_rt_elasticity;
-				net->ipv6.sysctl.ip6_rt_gc_min_interval =
-					saved_rt_min_interval;
-				goto retry;
-			}
-
-			net_warn_ratelimited("Neighbour table overflow\n");
-			dst_free(&rt->dst);
-			return NULL;
-		}
 	}
 
 	return rt;
@@ -899,10 +857,8 @@  static struct rt6_info *rt6_alloc_clone(struct rt6_info *ort,
 {
 	struct rt6_info *rt = ip6_rt_copy(ort, daddr);
 
-	if (rt) {
+	if (rt)
 		rt->rt6i_flags |= RTF_CACHE;
-		rt->n = neigh_clone(ort->n);
-	}
 	return rt;
 }
 
@@ -937,7 +893,6 @@  restart:
 	read_unlock_bh(&table->tb6_lock);
 
 	if (!(rt->rt6i_flags & (RTF_NONEXTHOP | RTF_GATEWAY))) {
-		BUG_ON(rt->n != NULL);
 		nrt = rt6_alloc_cow(rt, &fl6->daddr, &fl6->saddr);
 	} else if (!(rt->dst.flags & DST_HOST))
 		nrt = rt6_alloc_clone(rt, &fl6->daddr);
@@ -1499,12 +1454,6 @@  int ip6_route_add(struct fib6_config *cfg)
 	} else
 		rt->rt6i_prefsrc.plen = 0;
 
-	if (cfg->fc_flags & (RTF_GATEWAY | RTF_NONEXTHOP)) {
-		err = rt6_bind_neighbour(rt, dev);
-		if (err)
-			goto out;
-	}
-
 	rt->rt6i_flags = cfg->fc_flags;
 
 install_route:
@@ -1691,11 +1640,6 @@  static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 	if (!neigh)
 		return;
 
-	/* Duplicate redirect: silently ignore. */
-	old_neigh = rt->n;
-	if (neigh == old_neigh)
-		goto out;
-
 	/*
 	 *	We have finally decided to accept it.
 	 */
@@ -1716,7 +1660,6 @@  static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 		nrt->rt6i_flags &= ~RTF_GATEWAY;
 
 	nrt->rt6i_gateway = *(struct in6_addr *)neigh->primary_key;
-	nrt->n = neigh_clone(neigh);
 
 	if (ip6_ins_rt(nrt))
 		goto out;
@@ -2049,11 +1992,6 @@  struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
 		rt->rt6i_flags |= RTF_ANYCAST;
 	else
 		rt->rt6i_flags |= RTF_LOCAL;
-	err = rt6_bind_neighbour(rt, rt->dst.dev);
-	if (err) {
-		dst_free(&rt->dst);
-		return ERR_PTR(err);
-	}
 
 	rt->rt6i_dst.addr = *addr;
 	rt->rt6i_dst.plen = 128;
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index c984413..1282737 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -110,7 +110,6 @@  static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 
 	/* Sheit... I remember I did this right. Apparently,
 	 * it was magically lost, so this code needs audit */
-	xdst->u.rt6.n = neigh_clone(rt->n);
 	xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 						   RTF_LOCAL);
 	xdst->u.rt6.rt6i_metric = rt->rt6i_metric;