ipv6 fib: Use "Sweezle" to optimize addr_bit_test().

[~andy/linux] / net / ipv6 / ip6_fib.c

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 2f9847924fa51c95a342ab7bff4c54ea60552342..68119ef6286934be93c065c1e18934bc8067d617 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -127,12 +127,23 @@ static __inline__ u32 fib6_new_sernum(void)
 /*
  *     test bit
  */
+#if defined(__LITTLE_ENDIAN)
+# define BITOP_BE32_SWIZZLE    (0x1F & ~7)
+#else
+# define BITOP_BE32_SWIZZLE    0
+#endif
 
 static __inline__ __be32 addr_bit_set(void *token, int fn_bit)
 {
        __be32 *addr = token;
-
-       return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5];
+       /*
+        * Here,
+        *      1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
+        * is optimized version of
+        *      htonl(1 << ((~fn_bit)&0x1F))
+        * See include/asm-generic/bitops/le.h.
+        */
+       return (1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) & addr[fn_bit >> 5];
 }
 
 static __inline__ struct fib6_node * node_alloc(void)