net: Add skb_unclone() helper function.

This function will be used in next GRE_GSO patch. This patch does
not change any functionality.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Eric Dumazet <edumazet@google.com>

5 files changed, 5 insertions, 7 deletions

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index a69b4e4a02b5..2e7f1948216f 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -321,8 +321,7 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 
         /* We are going to _remove_ AH header to keep sockets happy,
          * so... Later this can change. */
-        if (skb_cloned(skb) &&
-            pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+        if (skb_unclone(skb, GFP_ATOMIC))
                 goto out;
 
         skb->ip_summed = CHECKSUM_NONE;
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 1211613c6c34..b6d30acb600c 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -590,7 +590,7 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
                 goto out_oversize;
 
         /* Head of list must not be cloned. */
-        if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
+        if (skb_unclone(head, GFP_ATOMIC))
                 goto out_nomem;
 
         /* If the first fragment is fragmented itself, we split
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 6182d90e97b0..fd0cea114b5d 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1331,7 +1331,7 @@ static void __pskb_trim_head(struct sk_buff *skb, int len)
 /* Remove acked data from a packet in the transmit queue. */
 int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len)
 {
-        if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+        if (skb_unclone(skb, GFP_ATOMIC))
                 return -ENOMEM;
 
         __pskb_trim_head(skb, len);
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 06814b6216dc..1f12c8b45864 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -132,7 +132,7 @@ int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
          * header and optional ESP marker bytes) and then modify the
          * protocol to ESP, and then call into the transform receiver.
          */
-        if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+        if (skb_unclone(skb, GFP_ATOMIC))
                 goto drop;
 
         /* Now we can update and verify the packet length... */
diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
index ddee0a099a2c..1162ace30838 100644
--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -142,8 +142,7 @@ static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
         for_each_input_rcu(rcv_notify_handlers, handler)
                 handler->handler(skb);
 
-        if (skb_cloned(skb) &&
-            (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+        if (err = skb_unclone(skb, GFP_ATOMIC))
                 goto out;
 
         if (x->props.flags & XFRM_STATE_DECAP_DSCP)