[PATCHv2] netfilter: Remove skb_is_nonlinear check from nf_conntrack_sip

[Jason Gunthorpe <jgunthorpe@obsidianresearch.com>]

At least the XEN net front driver always produces non linear skbs,
so the SIP module does nothing at all when used with that NIC.

Unconditionally linearize the skb..

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
---
 net/netfilter/nf_conntrack_sip.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

Patrick/Jan, thanks.. This is what I wanted to do in the first place,
but I couldn't convince myself it was safe, as no other nf code does
this..

Unfortunately I can no longer test it :(
 
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 4b57216..02d0b59 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -1275,13 +1275,10 @@ static int sip_help(struct sk_buff *skb,
 
 	nf_ct_refresh(ct, skb, sip_timeout * HZ);
 
-	if (!skb_is_nonlinear(skb))
-		dptr = skb->data + dataoff;
-	else {
-		pr_debug("Copy of skbuff not supported yet.\n");
-		return NF_ACCEPT;
-	}
+	if (unlikely(skb_linearize(skb)))
+		return NF_DROP;
 
+	dptr = skb->data + dataoff;
 	datalen = skb->len - dataoff;
 	if (datalen < strlen("SIP/2.0 200"))
 		return NF_ACCEPT;
-- 
1.6.0.4