[NET]: Uninline kfree_skb and allow NULL argument

o Uninline kfree_skb, which saves some 15k of object code on my notebook.

o Allow kfree_skb to be called with a NULL argument.

  Subsequent patches can remove conditional from drivers and further
  reduce source and object size.

Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2144952d1c6c..01abf1e8990b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -356,6 +356,24 @@ void __kfree_skb(struct sk_buff *skb)
 }
 
 /**
+ *      kfree_skb - free an sk_buff
+ *      @skb: buffer to free
+ *
+ *      Drop a reference to the buffer and free it if the usage count has
+ *      hit zero.
+ */
+void kfree_skb(struct sk_buff *skb)
+{
+        if (unlikely(!skb))
+                return;
+        if (likely(atomic_read(&skb->users) == 1))
+                smp_rmb();
+        else if (likely(!atomic_dec_and_test(&skb->users)))
+                return;
+        __kfree_skb(skb);
+}
+
+/**
  *      skb_clone       -       duplicate an sk_buff
  *      @skb: buffer to clone
  *      @gfp_mask: allocation priority
@@ -1799,6 +1817,7 @@ void __init skb_init(void)
 
 EXPORT_SYMBOL(___pskb_trim);
 EXPORT_SYMBOL(__kfree_skb);
+EXPORT_SYMBOL(kfree_skb);
 EXPORT_SYMBOL(__pskb_pull_tail);
 EXPORT_SYMBOL(__alloc_skb);
 EXPORT_SYMBOL(pskb_copy);