From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next] ipv6: optimize ipv6 addresses compares Date: Wed, 11 Jul 2012 07:05:57 +0200 Message-ID: <1341983157.3265.6792.camel@edumazet-glaptop> References: <1341978558.3265.6609.camel@edumazet-glaptop> <1341980090.13724.43.camel@joe2Laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev To: Joe Perches Return-path: Received: from mail-wi0-f170.google.com ([209.85.212.170]:59161 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750757Ab2GKFGB (ORCPT ); Wed, 11 Jul 2012 01:06:01 -0400 Received: by wibhq12 with SMTP id hq12so4222612wib.1 for ; Tue, 10 Jul 2012 22:06:00 -0700 (PDT) In-Reply-To: <1341980090.13724.43.camel@joe2Laptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet On Tue, 2012-07-10 at 21:14 -0700, Joe Perches wrote: > Come to think of it, this should probably be bool to > avoid anyone possibly using this in a sorting function. Yes, this sounds reasonable, thanks. [PATCH net-next v2] ipv6: optimize ipv6 addresses compares On 64 bit arches having efficient unaligned accesses (eg x86_64) we can use long words to reduce number of instructions for free. Joe Perches suggested to change ipv6_masked_addr_cmp() to return a bool instead of 'int', to make sure ipv6_masked_addr_cmp() cannot be used in a sorting function. Signed-off-by: Eric Dumazet Cc: Joe Perches --- include/net/ipv6.h | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/include/net/ipv6.h b/include/net/ipv6.h index aecf884..d4261d4 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -298,14 +298,23 @@ static inline int ipv6_addr_cmp(const struct in6_addr *a1, const struct in6_addr return memcmp(a1, a2, sizeof(struct in6_addr)); } -static inline int +static inline bool ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m, const struct in6_addr *a2) { +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 + const unsigned long *ul1 = (const unsigned long *)a1; + const unsigned long *ulm = (const unsigned long *)m; + const unsigned long *ul2 = (const unsigned long *)a2; + + return !!(((ul1[0] ^ ul2[0]) & ulm[0]) | + ((ul1[1] ^ ul2[1]) & ulm[1])); +#else return !!(((a1->s6_addr32[0] ^ a2->s6_addr32[0]) & m->s6_addr32[0]) | ((a1->s6_addr32[1] ^ a2->s6_addr32[1]) & m->s6_addr32[1]) | ((a1->s6_addr32[2] ^ a2->s6_addr32[2]) & m->s6_addr32[2]) | ((a1->s6_addr32[3] ^ a2->s6_addr32[3]) & m->s6_addr32[3])); +#endif } static inline void ipv6_addr_prefix(struct in6_addr *pfx, @@ -335,10 +344,17 @@ static inline void ipv6_addr_set(struct in6_addr *addr, static inline bool ipv6_addr_equal(const struct in6_addr *a1, const struct in6_addr *a2) { +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 + const unsigned long *ul1 = (const unsigned long *)a1; + const unsigned long *ul2 = (const unsigned long *)a2; + + return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL; +#else return ((a1->s6_addr32[0] ^ a2->s6_addr32[0]) | (a1->s6_addr32[1] ^ a2->s6_addr32[1]) | (a1->s6_addr32[2] ^ a2->s6_addr32[2]) | (a1->s6_addr32[3] ^ a2->s6_addr32[3])) == 0; +#endif } static inline bool __ipv6_prefix_equal(const __be32 *a1, const __be32 *a2, @@ -391,8 +407,14 @@ bool ip6_frag_match(struct inet_frag_queue *q, void *a); static inline bool ipv6_addr_any(const struct in6_addr *a) { +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 + const unsigned long *ul = (const unsigned long *)a; + + return (ul[0] | ul[1]) == 0UL; +#else return (a->s6_addr32[0] | a->s6_addr32[1] | a->s6_addr32[2] | a->s6_addr32[3]) == 0; +#endif } static inline bool ipv6_addr_loopback(const struct in6_addr *a)