[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, 6 insertions, 12 deletions

diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index d7080dd475ac..6413a30d9f68 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -332,6 +332,7 @@ static int
 ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
 {
         int diff;
+        int err;
         struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
 
         if (v->data_len < sizeof(*user_iph))
@@ -344,21 +345,14 @@ ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct ipq_queue_entry *e)
                 if (v->data_len > 0xFFFF)
                         return -EINVAL;
                 if (diff > skb_tailroom(e->skb)) {
-                        struct sk_buff *newskb;
-
-                        newskb = skb_copy_expand(e->skb,
-                                                 skb_headroom(e->skb),
-                                                 diff,
-                                                 GFP_ATOMIC);
-                        if (newskb == NULL) {
+                        err = pskb_expand_head(e->skb, 0,
+                                               diff - skb_tailroom(e->skb),
+                                               GFP_ATOMIC);
+                        if (err) {
                                 printk(KERN_WARNING "ip6_queue: OOM "
                                       "in mangle, dropping packet\n");
-                                return -ENOMEM;
+                                return err;
                         }
-                        if (e->skb->sk)
-                                skb_set_owner_w(newskb, e->skb->sk);
-                        kfree_skb(e->skb);
-                        e->skb = newskb;
                 }
                 skb_put(e->skb, diff);
         }