[PATCH net-next v2] ipv6: remove unnecessary call rt6_clean_expires

[PATCH net-next v2] ipv6: remove unnecessary call rt6_clean_expires

[roy.qing.li]

From: Li RongQing <roy.qing.li@gmail.com>

the from of dst_entry and rt6i_flags of rt6_info have been zeroed out in
ip6_blackhole_route or after calling ip6_dst_alloc, so it is unnecessary
to call rt6_clean_expires again.

Cc: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
---
 net/ipv6/route.c |    9 ++-------
 1 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 0607ee3..fd5dabf 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -996,8 +996,7 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
 			in6_dev_hold(rt->rt6i_idev);
 
 		rt->rt6i_gateway = ort->rt6i_gateway;
-		rt->rt6i_flags = ort->rt6i_flags;
-		rt6_clean_expires(rt);
+		rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
 		rt->rt6i_metric = 0;
 
 		memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));
@@ -1393,8 +1392,6 @@ int ip6_route_add(struct fib6_config *cfg)
 	if (cfg->fc_flags & RTF_EXPIRES)
 		rt6_set_expires(rt, jiffies +
 				clock_t_to_jiffies(cfg->fc_expires));
-	else
-		rt6_clean_expires(rt);
 
 	if (cfg->fc_protocol == RTPROT_UNSPEC)
 		cfg->fc_protocol = RTPROT_BOOT;
@@ -1803,12 +1800,10 @@ static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
 		rt->dst.lastuse = jiffies;
 
 		rt->rt6i_gateway = ort->rt6i_gateway;
-		rt->rt6i_flags = ort->rt6i_flags;
+		rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
 		if ((ort->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ==
 		    (RTF_DEFAULT | RTF_ADDRCONF))
 			rt6_set_from(rt, ort);
-		else
-			rt6_clean_expires(rt);
 		rt->rt6i_metric = 0;
 
 #ifdef CONFIG_IPV6_SUBTREES
-- 
1.7.4.1

Re: [PATCH net-next v2] ipv6: remove unnecessary call rt6_clean_expires

[David Miller]

From: roy.qing.li@gmail.com
Date: Thu, 20 Sep 2012 13:31:58 +0800

> From: Li RongQing <roy.qing.li@gmail.com>
> 
> the from of dst_entry and rt6i_flags of rt6_info have been zeroed out in
> ip6_blackhole_route or after calling ip6_dst_alloc, so it is unnecessary
> to call rt6_clean_expires again.
> 
> Cc: Gao feng <gaofeng@cn.fujitsu.com>
> Signed-off-by: Li RongQing <roy.qing.li@gmail.com>

I still don't like this change.

The rt6_clean_expires() calls actually do some work (clear the
RTF_EXPIRES) bit in two of the cases you are changing.

And more importantly, having the rt6_clean_expires() call makes
it easier to audit and make sure this is handled in all the
necessary situations.

The whole point of having an abstracted helper function is so
that we don't have code directly manipulating RTF_EXPIRES.

I'm not applying this patch, sorry.