ipv6: remove some useless RCU read lock

After this commit:
	commit 97cac0821af4474ec4ba3a9e7a36b98ed9b6db88
	Author: David S. Miller <davem@davemloft.net>
	Date:   Mon Jul 2 22:43:47 2012 -0700

	    ipv6: Store route neighbour in rt6_info struct.

we no longer use RCU to protect route neighbour.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 4 insertions, 24 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index a4f6263fddc..3dd4a37488d 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -123,16 +123,11 @@ static int ip6_finish_output2(struct sk_buff *skb)
                                 skb->len);
         }
 
-        rcu_read_lock();
         rt = (struct rt6_info *) dst;
         neigh = rt->n;
-        if (neigh) {
-                int res = dst_neigh_output(dst, neigh, skb);
+        if (neigh)
+                return dst_neigh_output(dst, neigh, skb);
 
-                rcu_read_unlock();
-                return res;
-        }
-        rcu_read_unlock();
         IP6_INC_STATS_BH(dev_net(dst->dev),
                          ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
         kfree_skb(skb);
@@ -983,7 +978,6 @@ static int ip6_dst_lookup_tail(struct sock *sk,
          * dst entry and replace it instead with the
          * dst entry of the nexthop router
          */
-        rcu_read_lock();
         rt = (struct rt6_info *) *dst;
         n = rt->n;
         if (n && !(n->nud_state & NUD_VALID)) {
@@ -991,7 +985,6 @@ static int ip6_dst_lookup_tail(struct sock *sk,
                 struct flowi6 fl_gw6;
                 int redirect;
 
-                rcu_read_unlock();
                 ifp = ipv6_get_ifaddr(net, &fl6->saddr,
                                       (*dst)->dev, 1);
 
@@ -1011,8 +1004,6 @@ static int ip6_dst_lookup_tail(struct sock *sk,
                         if ((err = (*dst)->error))
                                 goto out_err_release;
                 }
-        } else {
-                rcu_read_unlock();
         }
 #endif
 
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index a81c6790a64..399613b7972 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -451,10 +451,9 @@ static void rt6_probe(struct rt6_info *rt)
          * Router Reachability Probe MUST be rate-limited
          * to no more than one per minute.
          */
-        rcu_read_lock();
         neigh = rt ? rt->n : NULL;
         if (!neigh || (neigh->nud_state & NUD_VALID))
-                goto out;
+                return;
         read_lock_bh(&neigh->lock);
         if (!(neigh->nud_state & NUD_VALID) &&
             time_after(jiffies, neigh->updated + rt->rt6i_idev->cnf.rtr_probe_interval)) {
@@ -470,8 +469,6 @@ static void rt6_probe(struct rt6_info *rt)
         } else {
                 read_unlock_bh(&neigh->lock);
         }
-out:
-        rcu_read_unlock();
 }
 #else
 static inline void rt6_probe(struct rt6_info *rt)
@@ -498,7 +495,6 @@ static inline int rt6_check_neigh(struct rt6_info *rt)
         struct neighbour *neigh;
         int m;
 
-        rcu_read_lock();
         neigh = rt->n;
         if (rt->rt6i_flags & RTF_NONEXTHOP ||
             !(rt->rt6i_flags & RTF_GATEWAY))
@@ -516,7 +512,6 @@ static inline int rt6_check_neigh(struct rt6_info *rt)
                 read_unlock_bh(&neigh->lock);
         } else
                 m = 0;
-        rcu_read_unlock();
         return m;
 }
 
@@ -2496,15 +2491,11 @@ static int rt6_fill_node(struct net *net,
         if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
                 goto nla_put_failure;
 
-        rcu_read_lock();
         n = rt->n;
         if (n) {
-                if (nla_put(skb, RTA_GATEWAY, 16, &n->primary_key) < 0) {
-                        rcu_read_unlock();
+                if (nla_put(skb, RTA_GATEWAY, 16, &n->primary_key) < 0)
                         goto nla_put_failure;
-                }
         }
-        rcu_read_unlock();
 
         if (rt->dst.dev &&
             nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex))
@@ -2706,14 +2697,12 @@ static int rt6_info_route(struct rt6_info *rt, void *p_arg)
 #else
         seq_puts(m, "00000000000000000000000000000000 00 ");
 #endif
-        rcu_read_lock();
         n = rt->n;
         if (n) {
                 seq_printf(m, "%pi6", n->primary_key);
         } else {
                 seq_puts(m, "00000000000000000000000000000000");
         }
-        rcu_read_unlock();
         seq_printf(m, " %08x %08x %08x %08x %8s\n",
                    rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
                    rt->dst.__use, rt->rt6i_flags,