From 9f2e73345ad9466618edfec35d98c074f2e0570d Mon Sep 17 00:00:00 2001 From: =?utf8?q?YOSHIFUJI=20Hideaki=20/=20=E5=90=89=E8=97=A4=E8=8B=B1?= =?utf8?q?=E6=98=8E?= Date: Mon, 14 Jan 2013 07:09:54 +0000 Subject: [PATCH] ipv6: 64bit version of ipv6_addr_diff(). Introduce __ipv6_addr_diff64() to to find the first different bit between two addresses on 64bit architectures. 32bit version is still available as __ipv6_addr_diff32(), and __ipv6_addr_diff() automatically selects appropriate version. Signed-off-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- include/net/ipv6.h | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/include/net/ipv6.h b/include/net/ipv6.h index ed672080c690..ace1113bef85 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -507,7 +507,7 @@ static inline void ipv6_addr_set_v4mapped(const __be32 addr, * find the first different bit between two addresses * length of address must be a multiple of 32bits */ -static inline int __ipv6_addr_diff(const void *token1, const void *token2, int addrlen) +static inline int __ipv6_addr_diff32(const void *token1, const void *token2, int addrlen) { const __be32 *a1 = token1, *a2 = token2; int i; @@ -539,6 +539,33 @@ static inline int __ipv6_addr_diff(const void *token1, const void *token2, int a return addrlen << 5; } +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 +static inline int __ipv6_addr_diff64(const void *token1, const void *token2, int addrlen) +{ + const __be64 *a1 = token1, *a2 = token2; + int i; + + addrlen >>= 3; + + for (i = 0; i < addrlen; i++) { + __be64 xb = a1[i] ^ a2[i]; + if (xb) + return i * 64 + 63 - __fls(be64_to_cpu(xb)); + } + + return addrlen << 6; +} +#endif + +static inline int __ipv6_addr_diff(const void *token1, const void *token2, int addrlen) +{ +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 + if (__builtin_constant_p(addrlen) && !(addrlen & 7)) + return __ipv6_addr_diff64(token1, token2, addrlen); +#endif + return __ipv6_addr_diff32(token1, token2, addrlen); +} + static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_addr *a2) { return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr)); -- 2.30.2