[NET]: Replace skb_pull/skb_postpull_rcsum with skb_pull_rcsum

We're now starting to have quite a number of places that do skb_pull
followed immediately by an skb_postpull_rcsum.  We can merge these two
operations into one function with skb_pull_rcsum.  This makes sense
since most pull operations on receive skb's need to update the
checksum.

I've decided to make this out-of-line since it is fairly big and the
fast path where hardware checksums are enabled need to call
csum_partial anyway.

Since this is a brand new function we get to add an extra check on the
len argument.  As it is most callers of skb_pull ignore its return
value which essentially means that there is no check on the len
argument.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 75c963103b9f..613b9513f8b9 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1159,12 +1159,14 @@ static inline int skb_linearize(struct sk_buff *skb, gfp_t gfp)
  */
 
 static inline void skb_postpull_rcsum(struct sk_buff *skb,
-                                         const void *start, int len)
+                                      const void *start, unsigned int len)
 {
         if (skb->ip_summed == CHECKSUM_HW)
                 skb->csum = csum_sub(skb->csum, csum_partial(start, len, 0));
 }
 
+unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
+
 /**
  *      pskb_trim_rcsum - trim received skb and update checksum
  *      @skb: buffer to trim