bpf: use skb_expand_head in bpf_out_neigh_v4/6

Unlike skb_realloc_headroom, new helper skb_expand_head
does not allocate a new skb if possible.

Additionally this patch replaces commonly used dereferencing with variables.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/filter.c b/net/core/filter.c
index faf29fd..6f493ef 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2180,17 +2180,9 @@ static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb,
        skb->tstamp = 0;
 
        if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
-               struct sk_buff *skb2;
-
-               skb2 = skb_realloc_headroom(skb, hh_len);
-               if (unlikely(!skb2)) {
-                       kfree_skb(skb);
+               skb = skb_expand_head(skb, hh_len);
+               if (!skb)
                        return -ENOMEM;
-               }
-               if (skb->sk)
-                       skb_set_owner_w(skb2, skb->sk);
-               consume_skb(skb);
-               skb = skb2;
        }
 
        rcu_read_lock_bh();
@@ -2214,8 +2206,7 @@ static int bpf_out_neigh_v6(struct net *net, struct sk_buff *skb,
        }
        rcu_read_unlock_bh();
        if (dst)
-               IP6_INC_STATS(dev_net(dst->dev),
-                             ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
+               IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 out_drop:
        kfree_skb(skb);
        return -ENETDOWN;
@@ -2287,17 +2278,9 @@ static int bpf_out_neigh_v4(struct net *net, struct sk_buff *skb,
        skb->tstamp = 0;
 
        if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
-               struct sk_buff *skb2;
-
-               skb2 = skb_realloc_headroom(skb, hh_len);
-               if (unlikely(!skb2)) {
-                       kfree_skb(skb);
+               skb = skb_expand_head(skb, hh_len);
+               if (!skb)
                        return -ENOMEM;
-               }
-               if (skb->sk)
-                       skb_set_owner_w(skb2, skb->sk);
-               consume_skb(skb);
-               skb = skb2;
        }
 
        rcu_read_lock_bh();