[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/sm_statefuns.c b/net/sctp/sm_statefuns.c
index bf502c4..438e5dc 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -3115,7 +3115,7 @@
break;
ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
- if (ch_end > skb->tail)
+ if (ch_end > skb_tail_pointer(skb))
break;
if (SCTP_CID_SHUTDOWN_ACK == ch->type)
@@ -3130,7 +3130,7 @@
return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
ch = (sctp_chunkhdr_t *) ch_end;
- } while (ch_end < skb->tail);
+ } while (ch_end < skb_tail_pointer(skb));
if (ootb_shut_ack)
sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands);