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[SK_BUFF]: Convert skb->tail to sk_buff_data_t

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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>
This commit is contained in:
Arnaldo Carvalho de Melo
2007-04-19 20:29:13 -07:00
committed by David S. Miller
parent be8bd86321
commit 27a884dc3c
110 changed files with 396 additions and 329 deletions
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8
include/net/netlink.h
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@@ -525,7 +525,7 @@ static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
*/
static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
{
nlh->nlmsg_len = skb->tail - (unsigned char *) nlh;
nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
return skb->len;
}
@@ -538,7 +538,7 @@ static inline int nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
*/
static inline void *nlmsg_get_pos(struct sk_buff *skb)
{
return skb->tail;
return skb_tail_pointer(skb);
}
/**
@@ -940,7 +940,7 @@ static inline unsigned long nla_get_msecs(struct nlattr *nla)
*/
static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
{
struct nlattr *start = (struct nlattr *) skb->tail;
struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);
if (nla_put(skb, attrtype, 0, NULL) < 0)
return NULL;
@@ -960,7 +960,7 @@ static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
*/
static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
{
start->nla_len = skb->tail - (unsigned char *) start;
start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
return skb->len;
}