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ipv6: 64bit version of ipv6_addr_diff().

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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 <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
YOSHIFUJI Hideaki / 吉藤英明 2013-01-14 07:09:54 +00:00 committed by David S. Miller
parent 25d46f43a9
commit 9f2e73345a
1 changed files with 28 additions and 1 deletions
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29
include/net/ipv6.h
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@ -507,7 +507,7 @@ static inline void ipv6_addr_set_v4mapped(const __be32 addr,
* find the first different bit between two addresses * find the first different bit between two addresses
* length of address must be a multiple of 32bits * 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; const __be32 *a1 = token1, *a2 = token2;
int i; int i;
@ -539,6 +539,33 @@ static inline int __ipv6_addr_diff(const void *token1, const void *token2, int a
return addrlen << 5; 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) 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)); return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr));