dst: no need to take reference on DST_NOCACHE dsts

Since commit f8864972126899 ("ipv4: fix dst race in sk_dst_get()")
DST_NOCACHE dst_entries get freed by RCU. So there is no need to get a
reference on them when we are in rcu protected sections.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 2 insertions, 26 deletions

diff --git a/net/core/dst.c b/net/core/dst.c
index a028409ee438..e956ce6d1378 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -327,30 +327,6 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
 }
 EXPORT_SYMBOL(__dst_destroy_metrics_generic);
 
-/**
- * __skb_dst_set_noref - sets skb dst, without a reference
- * @skb: buffer
- * @dst: dst entry
- * @force: if force is set, use noref version even for DST_NOCACHE entries
- *
- * Sets skb dst, assuming a reference was not taken on dst
- * skb_dst_drop() should not dst_release() this dst
- */
-void __skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst, bool force)
-{
-        WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
-        /* If dst not in cache, we must take a reference, because
-         * dst_release() will destroy dst as soon as its refcount becomes zero
-         */
-        if (unlikely((dst->flags & DST_NOCACHE) && !force)) {
-                dst_hold(dst);
-                skb_dst_set(skb, dst);
-        } else {
-                skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
-        }
-}
-EXPORT_SYMBOL(__skb_dst_set_noref);
-
 /* Dirty hack. We did it in 2.2 (in __dst_free),
  * we have _very_ good reasons not to repeat
  * this mistake in 2.3, but we have no choice
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 1f933136155a..3aedbda7658a 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -343,7 +343,7 @@ __ip_vs_get_out_rt(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest,
         skb_dst_drop(skb);
         if (noref) {
                 if (!local)
-                        skb_dst_set_noref_force(skb, &rt->dst);
+                        skb_dst_set_noref(skb, &rt->dst);
                 else
                         skb_dst_set(skb, dst_clone(&rt->dst));
         } else
@@ -487,7 +487,7 @@ __ip_vs_get_out_rt_v6(int skb_af, struct sk_buff *skb, struct ip_vs_dest *dest,
         skb_dst_drop(skb);
         if (noref) {
                 if (!local)
-                        skb_dst_set_noref_force(skb, &rt->dst);
+                        skb_dst_set_noref(skb, &rt->dst);
                 else
                         skb_dst_set(skb, dst_clone(&rt->dst));
         } else