[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>
diff --git a/net/sctp/inqueue.c b/net/sctp/inqueue.c
index c30629e..88aa224 100644
--- a/net/sctp/inqueue.c
+++ b/net/sctp/inqueue.c
@@ -159,16 +159,16 @@
* 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subh.v = NULL; /* Subheader is no longer valid.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.