From mboxrd@z Thu Jan 1 00:00:00 1970 From: YOSHIFUJI Hideaki Subject: [PATCH 1/6] ipv6: 64bit version of ipv6_addr_diff(). Date: Tue, 15 Jan 2013 02:09:54 +0900 Message-ID: <50F43BE2.8090005@linux-ipv6.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Cc: yoshfuji@linux-ipv6.org To: davem@davemloft.net, netdev@vger.kernel.org Return-path: Received: from 94.43.138.210.xn.2iij.net ([210.138.43.94]:39833 "EHLO mail.st-paulia.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757227Ab3ANRJz (ORCPT ); Mon, 14 Jan 2013 12:09:55 -0500 Sender: netdev-owner@vger.kernel.org List-ID: 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 --- 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 ed67208..ace1113 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)); -- 1.7.9.5