From 37d41879224108d6c24578ba6a3eeafce106ce84 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 14 Oct 2007 00:39:18 -0700 Subject: [NETFILTER]: Do not copy skb in skb_make_writable Now that all callers of netfilter can guarantee that the skb is not shared, we no longer have to copy the skb in skb_make_writable. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/netfilter/core.c | 38 ++++++++++++++------------------------ 1 file changed, 14 insertions(+), 24 deletions(-) (limited to 'net/netfilter/core.c') diff --git a/net/netfilter/core.c b/net/netfilter/core.c index a523fa4136e..2c9e8e3652d 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -196,34 +196,24 @@ unlock: EXPORT_SYMBOL(nf_hook_slow); -int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len) +int skb_make_writable(struct sk_buff *skb, unsigned int writable_len) { - struct sk_buff *nskb; - - if (writable_len > (*pskb)->len) + if (writable_len > skb->len) return 0; /* Not exclusive use of packet? Must copy. */ - if (skb_cloned(*pskb) && !skb_clone_writable(*pskb, writable_len)) - goto copy_skb; - if (skb_shared(*pskb)) - goto copy_skb; - - return pskb_may_pull(*pskb, writable_len); - -copy_skb: - nskb = skb_copy(*pskb, GFP_ATOMIC); - if (!nskb) - return 0; - BUG_ON(skb_is_nonlinear(nskb)); - - /* Rest of kernel will get very unhappy if we pass it a - suddenly-orphaned skbuff */ - if ((*pskb)->sk) - skb_set_owner_w(nskb, (*pskb)->sk); - kfree_skb(*pskb); - *pskb = nskb; - return 1; + if (!skb_cloned(skb)) { + if (writable_len <= skb_headlen(skb)) + return 1; + } else if (skb_clone_writable(skb, writable_len)) + return 1; + + if (writable_len <= skb_headlen(skb)) + writable_len = 0; + else + writable_len -= skb_headlen(skb); + + return !!__pskb_pull_tail(skb, writable_len); } EXPORT_SYMBOL(skb_make_writable); -- cgit v1.2.3