[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>

2 files changed, 3 insertions, 4 deletions

diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 0245e40b51a1..f608c12e3e8b 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -1691,8 +1691,8 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
                     || ppp->npmode[npi] != NPMODE_PASS) {
                         kfree_skb(skb);
                 } else {
-                        skb_pull(skb, 2);       /* chop off protocol */
-                        skb_postpull_rcsum(skb, skb->data - 2, 2);
+                        /* chop off protocol */
+                        skb_pull_rcsum(skb, 2);
                         skb->dev = ppp->dev;
                         skb->protocol = htons(npindex_to_ethertype[npi]);
                         skb->mac.raw = skb->data;
diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index 9369f811075d..475dc930380f 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -337,8 +337,7 @@ static int pppoe_rcv_core(struct sock *sk, struct sk_buff *skb)
         if (sk->sk_state & PPPOX_BOUND) {
                 struct pppoe_hdr *ph = (struct pppoe_hdr *) skb->nh.raw;
                 int len = ntohs(ph->length);
-                skb_pull(skb, sizeof(struct pppoe_hdr));
-                skb_postpull_rcsum(skb, ph, sizeof(*ph));
+                skb_pull_rcsum(skb, sizeof(struct pppoe_hdr));
                 if (pskb_trim_rcsum(skb, len))
                         goto abort_kfree;