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ipv4: Inline neigh binding.

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Get rid of all of the useless and costly indirection
by doing the neigh hash table lookup directly inside
of the neighbour binding.

Rename from arp_bind_neighbour to rt_bind_neighbour.

Use new helpers {__,}ipv4_neigh_lookup()

In rt_bind_neighbour() get rid of useless tests which
are never true in the context this function is called,
namely dev is never NULL and the dst->neighbour is
always NULL.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Miller 2011-07-11 22:44:24 +00:00 committed by David S. Miller
parent e5b1de1f5e
commit 3769cffb1c
3 changed files with 59 additions and 28 deletions
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33
include/net/arp.h
View File

@ -15,6 +15,38 @@ static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd
return val * hash_rnd;
}
static inline struct neighbour *__ipv4_neigh_lookup(struct neigh_table *tbl, struct net_device *dev, u32 key)
{
struct neigh_hash_table *nht;
struct neighbour *n;
u32 hash_val;
rcu_read_lock_bh();
nht = rcu_dereference_bh(tbl->nht);
hash_val = arp_hashfn(key, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
n != NULL;
n = rcu_dereference_bh(n->next)) {
if (n->dev == dev && *(u32 *)n->primary_key == key) {
if (!atomic_inc_not_zero(&n->refcnt))
n = NULL;
break;
}
}
rcu_read_unlock_bh();
return n;
}
static inline struct neighbour *ipv4_neigh_lookup(struct neigh_table *tbl, struct net_device *dev, const __be32 *pkey)
{
struct neighbour *n = __ipv4_neigh_lookup(tbl, dev,
*(__force u32 *)pkey);
if (n)
return n;
return neigh_create(tbl, pkey, dev);
}
extern void arp_init(void);
extern int arp_find(unsigned char *haddr, struct sk_buff *skb);
extern int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);
@ -22,7 +54,6 @@ extern void arp_send(int type, int ptype, __be32 dest_ip,
struct net_device *dev, __be32 src_ip,
const unsigned char *dest_hw,
const unsigned char *src_hw, const unsigned char *th);
extern int arp_bind_neighbour(struct dst_entry *dst);
extern int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir);
extern void arp_ifdown(struct net_device *dev);

24
net/ipv4/arp.c
View File

@ -517,30 +517,6 @@ EXPORT_SYMBOL(arp_find);
/* END OF OBSOLETE FUNCTIONS */
int arp_bind_neighbour(struct dst_entry *dst)
{
struct net_device *dev = dst->dev;
struct neighbour *n = dst->neighbour;
if (dev == NULL)
return -EINVAL;
if (n == NULL) {
__be32 nexthop = ((struct rtable *)dst)->rt_gateway;
if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
nexthop = 0;
n = __neigh_lookup_errno(
#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
dev->type == ARPHRD_ATM ?
clip_tbl_hook :
#endif
&arp_tbl, &nexthop, dev);
if (IS_ERR(n))
return PTR_ERR(n);
dst->neighbour = n;
}
return 0;
}
/*
* Check if we can use proxy ARP for this path
*/

30
net/ipv4/route.c
View File

@ -108,6 +108,7 @@
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif
#include <net/atmclip.h>
#define RT_FL_TOS(oldflp4) \
((u32)(oldflp4->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
@ -1006,6 +1007,29 @@ static int slow_chain_length(const struct rtable *head)
return length >> FRACT_BITS;
}
static int rt_bind_neighbour(struct rtable *rt)
{
static const __be32 inaddr_any = 0;
struct net_device *dev = rt->dst.dev;
struct neigh_table *tbl = &arp_tbl;
const __be32 *nexthop;
struct neighbour *n;
#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
if (dev->type == ARPHRD_ATM)
tbl = clip_tbl_hook;
#endif
nexthop = &rt->rt_gateway;
if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
nexthop = &inaddr_any;
n = ipv4_neigh_lookup(tbl, dev, nexthop);
if (IS_ERR(n))
return PTR_ERR(n);
rt->dst.neighbour = n;
return 0;
}
static struct rtable *rt_intern_hash(unsigned hash, struct rtable *rt,
struct sk_buff *skb, int ifindex)
{
@ -1042,7 +1066,7 @@ restart:
rt->dst.flags |= DST_NOCACHE;
if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
int err = arp_bind_neighbour(&rt->dst);
int err = rt_bind_neighbour(rt);
if (err) {
if (net_ratelimit())
printk(KERN_WARNING
@ -1138,7 +1162,7 @@ restart:
route or unicast forwarding path.
*/
if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
int err = arp_bind_neighbour(&rt->dst);
int err = rt_bind_neighbour(rt);
if (err) {
spin_unlock_bh(rt_hash_lock_addr(hash));
@ -1599,7 +1623,7 @@ static int check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
rt->dst.neighbour = NULL;
rt->rt_gateway = peer->redirect_learned.a4;
if (arp_bind_neighbour(&rt->dst) ||
if (rt_bind_neighbour(rt) ||
!(rt->dst.neighbour->nud_state & NUD_VALID)) {
if (rt->dst.neighbour)
neigh_event_send(rt->dst.neighbour, NULL);