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Commit 60395a20 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by David S. Miller
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neigh: Factor out ___neigh_lookup_noref 



While looking at the mpls code I found myself writing yet another
version of neigh_lookup_noref.  We currently have __ipv4_lookup_noref
and __ipv6_lookup_noref.

So to make my work a little easier and to make it a smidge easier to
verify/maintain the mpls code in the future I stopped and wrote
___neigh_lookup_noref.  Then I rewote __ipv4_lookup_noref and
__ipv6_lookup_noref in terms of this new function.  I tested my new
version by verifying that the same code is generated in
ip_finish_output2 and ip6_finish_output2 where these functions are
inlined.

To get to ___neigh_lookup_noref I added a new neighbour cache table
function key_eq.  So that the static size of the key would be
available.

I also added __neigh_lookup_noref for people who want to to lookup
a neighbour table entry quickly but don't know which neibhgour table
they are going to look up.

Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2f56f6be

include/net/arp.h

+4 −15
Original line number Diff line number Diff line
@@ -9,28 +9,17 @@ 


extern struct neigh_table arp_tbl;



static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd)

static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 *hash_rnd)

{

	u32 key = *(const u32 *)pkey;

	u32 val = key ^ hash32_ptr(dev);



	return val * hash_rnd;

	return val * hash_rnd[0];

}



static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)

{

	struct neigh_hash_table *nht = rcu_dereference_bh(arp_tbl.nht);

	struct neighbour *n;

	u32 hash_val;



	hash_val = arp_hashfn(key, dev, nht->hash_rnd[0]) >> (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)

			return n;

	}



	return NULL;

	return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev);

}



static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)

include/net/ndisc.h

+1 −18
Original line number Diff line number Diff line
@@ -156,24 +156,7 @@ static inline u32 ndisc_hashfn(const void *pkey, const struct net_device *dev, _ 


static inline struct neighbour *__ipv6_neigh_lookup_noref(struct net_device *dev, const void *pkey)

{

	struct neigh_hash_table *nht;

	const u32 *p32 = pkey;

	struct neighbour *n;

	u32 hash_val;



	nht = rcu_dereference_bh(nd_tbl.nht);

	hash_val = ndisc_hashfn(pkey, 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)) {

		u32 *n32 = (u32 *) n->primary_key;

		if (n->dev == dev &&

		    ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |

		     (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0)

			return n;

	}



	return NULL;

	return ___neigh_lookup_noref(&nd_tbl, neigh_key_eq128, ndisc_hashfn, pkey, dev);

}



static inline struct neighbour *__ipv6_neigh_lookup(struct net_device *dev, const void *pkey)

include/net/neighbour.h

+52 −0
Original line number Diff line number Diff line
@@ -197,6 +197,7 @@ struct neigh_table { 
	__u32			(*hash)(const void *pkey,

					const struct net_device *dev,

					__u32 *hash_rnd);

	bool			(*key_eq)(const struct neighbour *, const void *pkey);

	int			(*constructor)(struct neighbour *);

	int			(*pconstructor)(struct pneigh_entry *);

	void			(*pdestructor)(struct pneigh_entry *);
@@ -247,6 +248,57 @@ static inline void *neighbour_priv(const struct neighbour *n) 
#define NEIGH_UPDATE_F_ISROUTER			0x40000000

#define NEIGH_UPDATE_F_ADMIN			0x80000000





static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)

{

	return *(const u16 *)n->primary_key == *(const u16 *)pkey;

}



static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)

{

	return *(const u32 *)n->primary_key == *(const u32 *)pkey;

}



static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)

{

	const u32 *n32 = (const u32 *)n->primary_key;

	const u32 *p32 = pkey;



	return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |

		(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;

}



static inline struct neighbour *___neigh_lookup_noref(

	struct neigh_table *tbl,

	bool (*key_eq)(const struct neighbour *n, const void *pkey),

	__u32 (*hash)(const void *pkey,

		      const struct net_device *dev,

		      __u32 *hash_rnd),

	const void *pkey,

	struct net_device *dev)

{

	struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);

	struct neighbour *n;

	u32 hash_val;



	hash_val = hash(pkey, 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 && key_eq(n, pkey))

			return n;

	}



	return NULL;

}



static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,

						     const void *pkey,

						     struct net_device *dev)

{

	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);

}



void neigh_table_init(int index, struct neigh_table *tbl);

int neigh_table_clear(int index, struct neigh_table *tbl);

struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,

net/core/neighbour.c

+5 −15
Original line number Diff line number Diff line
@@ -397,25 +397,15 @@ struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey, 
			       struct net_device *dev)

{

	struct neighbour *n;

	int key_len = tbl->key_len;

	u32 hash_val;

	struct neigh_hash_table *nht;



	NEIGH_CACHE_STAT_INC(tbl, lookups);



	rcu_read_lock_bh();

	nht = rcu_dereference_bh(tbl->nht);

	hash_val = tbl->hash(pkey, 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 (dev == n->dev && !memcmp(n->primary_key, pkey, key_len)) {

	n = __neigh_lookup_noref(tbl, pkey, dev);

	if (n) {

		if (!atomic_inc_not_zero(&n->refcnt))

			n = NULL;

		NEIGH_CACHE_STAT_INC(tbl, hits);

			break;

		}

	}



	rcu_read_unlock_bh();

net/decnet/dn_neigh.c

+6 −0
Original line number Diff line number Diff line
@@ -93,12 +93,18 @@ static u32 dn_neigh_hash(const void *pkey, 
	return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);

}



static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)

{

	return neigh_key_eq16(neigh, pkey);

}



struct neigh_table dn_neigh_table = {

	.family =			PF_DECnet,

	.entry_size =			NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),

	.key_len =			sizeof(__le16),

	.protocol =			cpu_to_be16(ETH_P_DNA_RT),

	.hash =				dn_neigh_hash,

	.key_eq =			dn_key_eq,

	.constructor =			dn_neigh_construct,

	.id =				"dn_neigh_cache",

	.parms ={