[SK_BUFF]: Convert skb->tail to sk_buff_data_t

So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)

Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 4 deletions

diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index c30629e17781..88aa22407549 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -159,16 +159,16 @@ struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
          * the skb->tail.
          */
         if (unlikely(skb_is_nonlinear(chunk->skb))) {
-                if (chunk->chunk_end > chunk->skb->tail)
-                        chunk->chunk_end = chunk->skb->tail;
+                if (chunk->chunk_end > skb_tail_pointer(chunk->skb))
+                        chunk->chunk_end = skb_tail_pointer(chunk->skb);
         }
         skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
         chunk->subh.v = NULL; /* Subheader is no longer valid.  */
 
-        if (chunk->chunk_end < chunk->skb->tail) {
+        if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) {
                 /* This is not a singleton */
                 chunk->singleton = 0;
-        } else if (chunk->chunk_end > chunk->skb->tail) {
+        } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
                 /* RFC 2960, Section 6.10  Bundling
                  *
                  * Partial chunks MUST NOT be placed in an SCTP packet.