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Date: Wed, 11 Jul 2012 07:05:57 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: Joe Perches <joe@...ches.com>
Cc: David Miller <davem@...emloft.net>, netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] ipv6: optimize ipv6 addresses compares
From: Eric Dumazet <edumazet@...gle.com>
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 <edumazet@...gle.com>
Cc: Joe Perches <joe@...ches.com>
---
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)
--
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