From 0b4419162aa6c4204843f3a13b48d9ab821d3167 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Mon, 16 Jun 2008 17:14:11 -0700 Subject: netns: introduce the net_hash_mix "salt" for hashes There are many possible ways to add this "salt", thus I made this patch to be the last in the series to change it if required. Currently I propose to use the struct net pointer itself as this salt, but since this pointer is most often cache-line aligned, shift this right to eliminate the bits, that are most often zeroed. After this, simply add this mix to prepared hashfn-s. For CONFIG_NET_NS=n case this salt is 0 and no changes in hashfn appear. Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller --- include/linux/udp.h | 3 ++- include/net/inet6_hashtables.h | 3 ++- include/net/inet_hashtables.h | 5 +++-- include/net/inet_sock.h | 3 ++- include/net/netns/hash.h | 21 +++++++++++++++++++++ 5 files changed, 30 insertions(+), 5 deletions(-) create mode 100644 include/net/netns/hash.h diff --git a/include/linux/udp.h b/include/linux/udp.h index 3deccac2e815..0cf5c4c0ec81 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -38,6 +38,7 @@ struct udphdr { #ifdef __KERNEL__ #include #include +#include static inline struct udphdr *udp_hdr(const struct sk_buff *skb) { @@ -48,7 +49,7 @@ static inline struct udphdr *udp_hdr(const struct sk_buff *skb) static inline int udp_hashfn(struct net *net, const unsigned num) { - return num & (UDP_HTABLE_SIZE - 1); + return (num + net_hash_mix(net)) & (UDP_HTABLE_SIZE - 1); } struct udp_sock { diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h index 72f13a9928e4..e48989f04c24 100644 --- a/include/net/inet6_hashtables.h +++ b/include/net/inet6_hashtables.h @@ -24,6 +24,7 @@ #include #include +#include struct inet_hashinfo; @@ -36,7 +37,7 @@ static inline unsigned int inet6_ehashfn(struct net *net, return jhash_3words((__force u32)laddr->s6_addr32[3], (__force u32)faddr->s6_addr32[3], - ports, inet_ehash_secret); + ports, inet_ehash_secret + net_hash_mix(net)); } static inline int inet6_sk_ehashfn(const struct sock *sk) diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h index 26336cdcdc11..bb619d80f2e2 100644 --- a/include/net/inet_hashtables.h +++ b/include/net/inet_hashtables.h @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -204,7 +205,7 @@ extern void inet_bind_bucket_destroy(struct kmem_cache *cachep, static inline int inet_bhashfn(struct net *net, const __u16 lport, const int bhash_size) { - return lport & (bhash_size - 1); + return (lport + net_hash_mix(net)) & (bhash_size - 1); } extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, @@ -213,7 +214,7 @@ extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, /* These can have wildcards, don't try too hard. */ static inline int inet_lhashfn(struct net *net, const unsigned short num) { - return num & (INET_LHTABLE_SIZE - 1); + return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); } static inline int inet_sk_listen_hashfn(const struct sock *sk) diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index 85bb420c5d86..643e26be058e 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -25,6 +25,7 @@ #include #include #include +#include /** struct ip_options - IP Options * @@ -178,7 +179,7 @@ static inline unsigned int inet_ehashfn(struct net *net, return jhash_3words((__force __u32) laddr, (__force __u32) faddr, ((__u32) lport) << 16 | (__force __u32)fport, - inet_ehash_secret); + inet_ehash_secret + net_hash_mix(net)); } static inline int inet_sk_ehashfn(const struct sock *sk) diff --git a/include/net/netns/hash.h b/include/net/netns/hash.h new file mode 100644 index 000000000000..548d78f2cc47 --- /dev/null +++ b/include/net/netns/hash.h @@ -0,0 +1,21 @@ +#ifndef __NET_NS_HASH_H__ +#define __NET_NS_HASH_H__ + +#include + +struct net; + +static inline unsigned net_hash_mix(struct net *net) +{ +#ifdef CONFIG_NET_NS + /* + * shift this right to eliminate bits, that are + * always zeroed + */ + + return (unsigned)(((unsigned long)net) >> L1_CACHE_SHIFT); +#else + return 0; +#endif +} +#endif -- cgit v1.2.3-59-g8ed1b