[NETFILTER]: Avoid skb_copy/pskb_copy/skb_realloc_headroom

This patch replaces unnecessary uses of skb_copy, pskb_copy and
skb_realloc_headroom by functions such as skb_make_writable and
pskb_expand_head.

This allows us to remove the double pointers later.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 22 deletions

diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index b44192924f9..d1e3012d891 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -3,6 +3,7 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4.h>
 #include <linux/ip.h>
+#include <linux/skbuff.h>
 #include <net/route.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
@@ -66,17 +67,10 @@ int ip_route_me_harder(struct sk_buff **pskb, unsigned addr_type)
 
         /* Change in oif may mean change in hh_len. */
         hh_len = (*pskb)->dst->dev->hard_header_len;
-        if (skb_headroom(*pskb) < hh_len) {
-                struct sk_buff *nskb;
-
-                nskb = skb_realloc_headroom(*pskb, hh_len);
-                if (!nskb)
-                        return -1;
-                if ((*pskb)->sk)
-                        skb_set_owner_w(nskb, (*pskb)->sk);
-                kfree_skb(*pskb);
-                *pskb = nskb;
-        }
+        if (skb_headroom(*pskb) < hh_len &&
+            pskb_expand_head(*pskb, hh_len - skb_headroom(*pskb), 0,
+                             GFP_ATOMIC))
+                return -1;
 
         return 0;
 }
@@ -107,17 +101,10 @@ int ip_xfrm_me_harder(struct sk_buff **pskb)
 
         /* Change in oif may mean change in hh_len. */
         hh_len = (*pskb)->dst->dev->hard_header_len;
-        if (skb_headroom(*pskb) < hh_len) {
-                struct sk_buff *nskb;
-
-                nskb = skb_realloc_headroom(*pskb, hh_len);
-                if (!nskb)
-                        return -1;
-                if ((*pskb)->sk)
-                        skb_set_owner_w(nskb, (*pskb)->sk);
-                kfree_skb(*pskb);
-                *pskb = nskb;
-        }
+        if (skb_headroom(*pskb) < hh_len &&
+            pskb_expand_head(*pskb, hh_len - skb_headroom(*pskb), 0,
+                             GFP_ATOMIC))
+                return -1;
         return 0;
 }
 EXPORT_SYMBOL(ip_xfrm_me_harder);