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Message-Id: <20110712.014424.120003225201174608.davem@davemloft.net>
Date: Tue, 12 Jul 2011 01:44:24 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
Subject: [PATCH] ipv4: Inline neigh binding.
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@...emloft.net>
---
include/net/arp.h | 33 ++++++++++++++++++++++++++++++++-
net/ipv4/arp.c | 24 ------------------------
net/ipv4/route.c | 30 +++++++++++++++++++++++++++---
3 files changed, 59 insertions(+), 28 deletions(-)
diff --git a/include/net/arp.h b/include/net/arp.h
index 723bde5..5e669e6 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -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);
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 4412b57..3e55456 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -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
*/
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a8ccd9b..c6388e8 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -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);
--
1.7.5.4
--
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