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>

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index a4f6263..3dd4a37 100644 (file)
--- 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 a81c679..399613b 100644 (file)
--- 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,