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neigh: Factor out ___neigh_lookup_noref

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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: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric W. Biederman 2015-03-03 17:10:44 -06:00 committed by David S. Miller
parent 2f56f6be47
commit 60395a20ff
7 changed files with 83 additions and 49 deletions
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19
include/net/arp.h
View File

@ -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)

19
include/net/ndisc.h
View File

@ -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)

52
include/net/neighbour.h
View File

@ -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,

20
net/core/neighbour.c
View File

@ -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)) {
if (!atomic_inc_not_zero(&n->refcnt))
n = NULL;
NEIGH_CACHE_STAT_INC(tbl, hits);
break;
}
n = __neigh_lookup_noref(tbl, pkey, dev);
if (n) {
if (!atomic_inc_not_zero(&n->refcnt))
n = NULL;
NEIGH_CACHE_STAT_INC(tbl, hits);
}
rcu_read_unlock_bh();

6
net/decnet/dn_neigh.c
View File

@ -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 ={

9
net/ipv4/arp.c
View File

@ -122,6 +122,7 @@
* Interface to generic neighbour cache.
*/
static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
static bool arp_key_eq(const struct neighbour *n, const void *pkey);
static int arp_constructor(struct neighbour *neigh);
static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
@ -154,6 +155,7 @@ struct neigh_table arp_tbl = {
.key_len = 4,
.protocol = cpu_to_be16(ETH_P_IP),
.hash = arp_hash,
.key_eq = arp_key_eq,
.constructor = arp_constructor,
.proxy_redo = parp_redo,
.id = "arp_cache",
@ -209,7 +211,12 @@ static u32 arp_hash(const void *pkey,
const struct net_device *dev,
__u32 *hash_rnd)
{
return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd);
return arp_hashfn(pkey, dev, hash_rnd);
}
static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
{
return neigh_key_eq32(neigh, pkey);
}
static int arp_constructor(struct neighbour *neigh)

7
net/ipv6/ndisc.c
View File

@ -84,6 +84,7 @@ do { \
static u32 ndisc_hash(const void *pkey,
const struct net_device *dev,
__u32 *hash_rnd);
static bool ndisc_key_eq(const struct neighbour *neigh, const void *pkey);
static int ndisc_constructor(struct neighbour *neigh);
static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb);
static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb);
@ -119,6 +120,7 @@ struct neigh_table nd_tbl = {
.key_len = sizeof(struct in6_addr),
.protocol = cpu_to_be16(ETH_P_IPV6),
.hash = ndisc_hash,
.key_eq = ndisc_key_eq,
.constructor = ndisc_constructor,
.pconstructor = pndisc_constructor,
.pdestructor = pndisc_destructor,
@ -295,6 +297,11 @@ static u32 ndisc_hash(const void *pkey,
return ndisc_hashfn(pkey, dev, hash_rnd);
}
static bool ndisc_key_eq(const struct neighbour *n, const void *pkey)
{
return neigh_key_eq128(n, pkey);
}
static int ndisc_constructor(struct neighbour *neigh)
{
struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key;