diff options
Diffstat (limited to 'fs/ceph/crush/hash.h')
-rw-r--r-- | fs/ceph/crush/hash.h | 92 |
1 files changed, 7 insertions, 85 deletions
diff --git a/fs/ceph/crush/hash.h b/fs/ceph/crush/hash.h index 42f3312783a..9ce89f85dc7 100644 --- a/fs/ceph/crush/hash.h +++ b/fs/ceph/crush/hash.h @@ -1,90 +1,12 @@ #ifndef _CRUSH_HASH_H #define _CRUSH_HASH_H -/* - * Robert Jenkins' function for mixing 32-bit values - * http://burtleburtle.net/bob/hash/evahash.html - * a, b = random bits, c = input and output - */ -#define crush_hashmix(a, b, c) do { \ - a = a-b; a = a-c; a = a^(c>>13); \ - b = b-c; b = b-a; b = b^(a<<8); \ - c = c-a; c = c-b; c = c^(b>>13); \ - a = a-b; a = a-c; a = a^(c>>12); \ - b = b-c; b = b-a; b = b^(a<<16); \ - c = c-a; c = c-b; c = c^(b>>5); \ - a = a-b; a = a-c; a = a^(c>>3); \ - b = b-c; b = b-a; b = b^(a<<10); \ - c = c-a; c = c-b; c = c^(b>>15); \ - } while (0) - -#define crush_hash_seed 1315423911 - -static inline __u32 crush_hash32(__u32 a) -{ - __u32 hash = crush_hash_seed ^ a; - __u32 b = a; - __u32 x = 231232; - __u32 y = 1232; - crush_hashmix(b, x, hash); - crush_hashmix(y, a, hash); - return hash; -} - -static inline __u32 crush_hash32_2(__u32 a, __u32 b) -{ - __u32 hash = crush_hash_seed ^ a ^ b; - __u32 x = 231232; - __u32 y = 1232; - crush_hashmix(a, b, hash); - crush_hashmix(x, a, hash); - crush_hashmix(b, y, hash); - return hash; -} - -static inline __u32 crush_hash32_3(__u32 a, __u32 b, __u32 c) -{ - __u32 hash = crush_hash_seed ^ a ^ b ^ c; - __u32 x = 231232; - __u32 y = 1232; - crush_hashmix(a, b, hash); - crush_hashmix(c, x, hash); - crush_hashmix(y, a, hash); - crush_hashmix(b, x, hash); - crush_hashmix(y, c, hash); - return hash; -} - -static inline __u32 crush_hash32_4(__u32 a, __u32 b, __u32 c, - __u32 d) -{ - __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d; - __u32 x = 231232; - __u32 y = 1232; - crush_hashmix(a, b, hash); - crush_hashmix(c, d, hash); - crush_hashmix(a, x, hash); - crush_hashmix(y, b, hash); - crush_hashmix(c, x, hash); - crush_hashmix(y, d, hash); - return hash; -} - -static inline __u32 crush_hash32_5(__u32 a, __u32 b, __u32 c, - __u32 d, __u32 e) -{ - __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d ^ e; - __u32 x = 231232; - __u32 y = 1232; - crush_hashmix(a, b, hash); - crush_hashmix(c, d, hash); - crush_hashmix(e, x, hash); - crush_hashmix(y, a, hash); - crush_hashmix(b, x, hash); - crush_hashmix(y, c, hash); - crush_hashmix(d, x, hash); - crush_hashmix(y, e, hash); - return hash; -} +extern __u32 crush_hash32(__u32 a); +extern __u32 crush_hash32_2(__u32 a, __u32 b); +extern __u32 crush_hash32_3(__u32 a, __u32 b, __u32 c); +extern __u32 crush_hash32_4(__u32 a, __u32 b, __u32 c, + __u32 d); +extern __u32 crush_hash32_5(__u32 a, __u32 b, __u32 c, + __u32 d, __u32 e); #endif |