From a46632d3497a61537496607d3b46ce549a877ac1 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sun, 16 Sep 2007 16:21:16 -0700
Subject: [PATCH] --- yaml --- r: 65000 b: refs/heads/master c:
 d9cc20484e5e48c6a5deb4387c20fd45bfbdde8c h: refs/heads/master v: v3

---
 [refs]                          |  2 +-
 trunk/drivers/net/pppoe.c       |  2 +-
 trunk/include/linux/skbuff.h    | 40 +++++++++++++++++++++++++--------
 trunk/net/bridge/br_netfilter.c |  2 +-
 4 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/[refs] b/[refs]
index b3ecc01877e2..e2853b4f474a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e081e1e3ef4682802ac63b1e5e26158fb9ca9e90
+refs/heads/master: d9cc20484e5e48c6a5deb4387c20fd45bfbdde8c
diff --git a/trunk/drivers/net/pppoe.c b/trunk/drivers/net/pppoe.c
index bac36546e0bf..0d7f570b9a54 100644
--- a/trunk/drivers/net/pppoe.c
+++ b/trunk/drivers/net/pppoe.c
@@ -860,7 +860,7 @@ static int __pppoe_xmit(struct sock *sk, struct sk_buff *skb)
 	/* Copy the data if there is no space for the header or if it's
 	 * read-only.
 	 */
-	if (skb_cow(skb, sizeof(*ph) + dev->hard_header_len))
+	if (skb_cow_head(skb, sizeof(*ph) + dev->hard_header_len))
 		goto abort;
 
 	__skb_push(skb, sizeof(*ph));
diff --git a/trunk/include/linux/skbuff.h b/trunk/include/linux/skbuff.h
index 93c27f71122a..a656cecd373c 100644
--- a/trunk/include/linux/skbuff.h
+++ b/trunk/include/linux/skbuff.h
@@ -1352,6 +1352,22 @@ static inline int skb_clone_writable(struct sk_buff *skb, int len)
 	       skb_headroom(skb) + len <= skb->hdr_len;
 }
 
+static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
+			    int cloned)
+{
+	int delta = 0;
+
+	if (headroom < NET_SKB_PAD)
+		headroom = NET_SKB_PAD;
+	if (headroom > skb_headroom(skb))
+		delta = headroom - skb_headroom(skb);
+
+	if (delta || cloned)
+		return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
+					GFP_ATOMIC);
+	return 0;
+}
+
 /**
  *	skb_cow - copy header of skb when it is required
  *	@skb: buffer to cow
@@ -1366,16 +1382,22 @@ static inline int skb_clone_writable(struct sk_buff *skb, int len)
  */
 static inline int skb_cow(struct sk_buff *skb, unsigned int headroom)
 {
-	int delta = (headroom > NET_SKB_PAD ? headroom : NET_SKB_PAD) -
-			skb_headroom(skb);
-
-	if (delta < 0)
-		delta = 0;
+	return __skb_cow(skb, headroom, skb_cloned(skb));
+}
 
-	if (delta || skb_cloned(skb))
-		return pskb_expand_head(skb, (delta + (NET_SKB_PAD-1)) &
-				~(NET_SKB_PAD-1), 0, GFP_ATOMIC);
-	return 0;
+/**
+ *	skb_cow_head - skb_cow but only making the head writable
+ *	@skb: buffer to cow
+ *	@headroom: needed headroom
+ *
+ *	This function is identical to skb_cow except that we replace the
+ *	skb_cloned check by skb_header_cloned.  It should be used when
+ *	you only need to push on some header and do not need to modify
+ *	the data.
+ */
+static inline int skb_cow_head(struct sk_buff *skb, unsigned int headroom)
+{
+	return __skb_cow(skb, headroom, skb_header_cloned(skb));
 }
 
 /**
diff --git a/trunk/net/bridge/br_netfilter.c b/trunk/net/bridge/br_netfilter.c
index 3ee2022928e3..fc13130035e7 100644
--- a/trunk/net/bridge/br_netfilter.c
+++ b/trunk/net/bridge/br_netfilter.c
@@ -183,7 +183,7 @@ int nf_bridge_copy_header(struct sk_buff *skb)
 	int err;
 	int header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
 
-	err = skb_cow(skb, header_size);
+	err = skb_cow_head(skb, header_size);
 	if (err)
 		return err;