2 # include <linux/crush/hash.h>
8 * Robert Jenkins' function for mixing 32-bit values
9 * http://burtleburtle.net/bob/hash/evahash.html
10 * a, b = random bits, c = input and output
12 #define crush_hashmix(a, b, c) do { \
13 a = a-b; a = a-c; a = a^(c>>13); \
14 b = b-c; b = b-a; b = b^(a<<8); \
15 c = c-a; c = c-b; c = c^(b>>13); \
16 a = a-b; a = a-c; a = a^(c>>12); \
17 b = b-c; b = b-a; b = b^(a<<16); \
18 c = c-a; c = c-b; c = c^(b>>5); \
19 a = a-b; a = a-c; a = a^(c>>3); \
20 b = b-c; b = b-a; b = b^(a<<10); \
21 c = c-a; c = c-b; c = c^(b>>15); \
24 #define crush_hash_seed 1315423911
26 static __u32 crush_hash32_rjenkins1(__u32 a)
28 __u32 hash = crush_hash_seed ^ a;
32 crush_hashmix(b, x, hash);
33 crush_hashmix(y, a, hash);
37 static __u32 crush_hash32_rjenkins1_2(__u32 a, __u32 b)
39 __u32 hash = crush_hash_seed ^ a ^ b;
42 crush_hashmix(a, b, hash);
43 crush_hashmix(x, a, hash);
44 crush_hashmix(b, y, hash);
48 static __u32 crush_hash32_rjenkins1_3(__u32 a, __u32 b, __u32 c)
50 __u32 hash = crush_hash_seed ^ a ^ b ^ c;
53 crush_hashmix(a, b, hash);
54 crush_hashmix(c, x, hash);
55 crush_hashmix(y, a, hash);
56 crush_hashmix(b, x, hash);
57 crush_hashmix(y, c, hash);
61 static __u32 crush_hash32_rjenkins1_4(__u32 a, __u32 b, __u32 c, __u32 d)
63 __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d;
66 crush_hashmix(a, b, hash);
67 crush_hashmix(c, d, hash);
68 crush_hashmix(a, x, hash);
69 crush_hashmix(y, b, hash);
70 crush_hashmix(c, x, hash);
71 crush_hashmix(y, d, hash);
75 static __u32 crush_hash32_rjenkins1_5(__u32 a, __u32 b, __u32 c, __u32 d,
78 __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d ^ e;
81 crush_hashmix(a, b, hash);
82 crush_hashmix(c, d, hash);
83 crush_hashmix(e, x, hash);
84 crush_hashmix(y, a, hash);
85 crush_hashmix(b, x, hash);
86 crush_hashmix(y, c, hash);
87 crush_hashmix(d, x, hash);
88 crush_hashmix(y, e, hash);
93 __u32 crush_hash32(int type, __u32 a)
96 case CRUSH_HASH_RJENKINS1:
97 return crush_hash32_rjenkins1(a);
103 __u32 crush_hash32_2(int type, __u32 a, __u32 b)
106 case CRUSH_HASH_RJENKINS1:
107 return crush_hash32_rjenkins1_2(a, b);
113 __u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c)
116 case CRUSH_HASH_RJENKINS1:
117 return crush_hash32_rjenkins1_3(a, b, c);
123 __u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d)
126 case CRUSH_HASH_RJENKINS1:
127 return crush_hash32_rjenkins1_4(a, b, c, d);
133 __u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d, __u32 e)
136 case CRUSH_HASH_RJENKINS1:
137 return crush_hash32_rjenkins1_5(a, b, c, d, e);
143 const char *crush_hash_name(int type)
146 case CRUSH_HASH_RJENKINS1: