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authorYOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@linux-ipv6.org>2013-01-14 07:09:54 +0000
committerDavid S. Miller <davem@davemloft.net>2013-01-14 13:17:00 -0500
commit9f2e73345ad9466618edfec35d98c074f2e0570d (patch)
tree504a464901e3a7b5054a288b8e86874f267fae47 /include
parent25d46f43a911b08c5aa8c8fd4fe7fa9b36445068 (diff)
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 <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/ipv6.h29
1 files changed, 28 insertions, 1 deletions
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index ed672080c69..ace1113bef8 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));