From ddbe503203855939946430e39bae58de11b70b69 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Jul 2012 08:11:12 +0000 Subject: ipv6: add ipv6_addr_hash() helper Introduce ipv6_addr_hash() helper doing a XOR on all bits of an IPv6 address, with an optimized x86_64 version. Use it in flow dissector, as suggested by Andrew McGregor, to reduce hash collision probabilities in fq_codel (and other users of flow dissector) Use it in ip6_tunnel.c and use more bit shuffling, as suggested by David Laight, as existing hash was ignoring most of them. Use it in sunrpc and use more bit shuffling, using hash_32(). Use it in net/ipv6/addrconf.c, using hash_32() as well. As a cleanup, use it in net/ipv4/tcp_metrics.c Signed-off-by: Eric Dumazet Reported-by: Andrew McGregor Cc: Dave Taht Cc: Tom Herbert Cc: David Laight Cc: Joe Perches Signed-off-by: David S. Miller --- net/sunrpc/svcauth_unix.c | 22 ++++------------------ 1 file changed, 4 insertions(+), 18 deletions(-) (limited to 'net/sunrpc/svcauth_unix.c') diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index 2777fa896645..4d0129203733 100644 --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -104,23 +104,9 @@ static void ip_map_put(struct kref *kref) kfree(im); } -#if IP_HASHBITS == 8 -/* hash_long on a 64 bit machine is currently REALLY BAD for - * IP addresses in reverse-endian (i.e. on a little-endian machine). - * So use a trivial but reliable hash instead - */ -static inline int hash_ip(__be32 ip) -{ - int hash = (__force u32)ip ^ ((__force u32)ip>>16); - return (hash ^ (hash>>8)) & 0xff; -} -#endif -static inline int hash_ip6(struct in6_addr ip) +static inline int hash_ip6(const struct in6_addr *ip) { - return (hash_ip(ip.s6_addr32[0]) ^ - hash_ip(ip.s6_addr32[1]) ^ - hash_ip(ip.s6_addr32[2]) ^ - hash_ip(ip.s6_addr32[3])); + return hash_32(ipv6_addr_hash(ip), IP_HASHBITS); } static int ip_map_match(struct cache_head *corig, struct cache_head *cnew) { @@ -301,7 +287,7 @@ static struct ip_map *__ip_map_lookup(struct cache_detail *cd, char *class, ip.m_addr = *addr; ch = sunrpc_cache_lookup(cd, &ip.h, hash_str(class, IP_HASHBITS) ^ - hash_ip6(*addr)); + hash_ip6(addr)); if (ch) return container_of(ch, struct ip_map, h); @@ -331,7 +317,7 @@ static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm, ip.h.expiry_time = expiry; ch = sunrpc_cache_update(cd, &ip.h, &ipm->h, hash_str(ipm->m_class, IP_HASHBITS) ^ - hash_ip6(ipm->m_addr)); + hash_ip6(&ipm->m_addr)); if (!ch) return -ENOMEM; cache_put(ch, cd); -- cgit