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inet: frags: get rid of nf_ct_frag6_skb_cb/NFCT_FRAG6_CB

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nf_ct_frag6_queue() uses skb->cb[] to store the fragment offset,
meaning that we could use two cache lines per skb when finding
the insertion point, if for some reason inet6_skb_parm size
is increased in the future.

By using skb->ip_defrag_offset instead of skb->cb[] we pack all the fields
in a single cache line, matching what we did for IPv4.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2018-03-31 12:59:00 -07:00 committed by David S. Miller
parent 219badfaad
commit f2d1c724fc
1 changed files with 11 additions and 18 deletions
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29
net/ipv6/netfilter/nf_conntrack_reasm.c
View File

@ -52,14 +52,6 @@
static const char nf_frags_cache_name[] = "nf-frags";
struct nf_ct_frag6_skb_cb
{
struct inet6_skb_parm h;
int offset;
};
#define NFCT_FRAG6_CB(skb) ((struct nf_ct_frag6_skb_cb *)((skb)->cb))
static struct inet_frags nf_frags;
#ifdef CONFIG_SYSCTL
@ -270,13 +262,13 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
* this fragment, right?
*/
prev = fq->q.fragments_tail;
if (!prev || NFCT_FRAG6_CB(prev)->offset < offset) {
if (!prev || prev->ip_defrag_offset < offset) {
next = NULL;
goto found;
}
prev = NULL;
for (next = fq->q.fragments; next != NULL; next = next->next) {
if (NFCT_FRAG6_CB(next)->offset >= offset)
if (next->ip_defrag_offset >= offset)
break; /* bingo! */
prev = next;
}
@ -292,14 +284,19 @@ found:
/* Check for overlap with preceding fragment. */
if (prev &&
(NFCT_FRAG6_CB(prev)->offset + prev->len) > offset)
(prev->ip_defrag_offset + prev->len) > offset)
goto discard_fq;
/* Look for overlap with succeeding segment. */
if (next && NFCT_FRAG6_CB(next)->offset < end)
if (next && next->ip_defrag_offset < end)
goto discard_fq;
NFCT_FRAG6_CB(skb)->offset = offset;
/* Note : skb->ip_defrag_offset and skb->dev share the same location */
if (skb->dev)
fq->iif = skb->dev->ifindex;
/* Makes sure compiler wont do silly aliasing games */
barrier();
skb->ip_defrag_offset = offset;
/* Insert this fragment in the chain of fragments. */
skb->next = next;
@ -310,10 +307,6 @@ found:
else
fq->q.fragments = skb;
if (skb->dev) {
fq->iif = skb->dev->ifindex;
skb->dev = NULL;
}
fq->q.stamp = skb->tstamp;
fq->q.meat += skb->len;
fq->ecn |= ecn;
@ -357,7 +350,7 @@ nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *prev, struct net_devic
inet_frag_kill(&fq->q);
WARN_ON(head == NULL);
WARN_ON(NFCT_FRAG6_CB(head)->offset != 0);
WARN_ON(head->ip_defrag_offset != 0);
ecn = ip_frag_ecn_table[fq->ecn];
if (unlikely(ecn == 0xff))