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-rw-r--r--lib/random32.c38
1 files changed, 17 insertions, 21 deletions
diff --git a/lib/random32.c b/lib/random32.c
index 217d5c4b666d..870dc3fc0f0f 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -39,13 +39,16 @@
39#include <linux/jiffies.h> 39#include <linux/jiffies.h>
40#include <linux/random.h> 40#include <linux/random.h>
41 41
42struct rnd_state {
43 u32 s1, s2, s3;
44};
45
46static DEFINE_PER_CPU(struct rnd_state, net_rand_state); 42static DEFINE_PER_CPU(struct rnd_state, net_rand_state);
47 43
48static u32 __random32(struct rnd_state *state) 44/**
45 * prandom32 - seeded pseudo-random number generator.
46 * @state: pointer to state structure holding seeded state.
47 *
48 * This is used for pseudo-randomness with no outside seeding.
49 * For more random results, use random32().
50 */
51u32 prandom32(struct rnd_state *state)
49{ 52{
50#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b) 53#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
51 54
@@ -55,14 +58,7 @@ static u32 __random32(struct rnd_state *state)
55 58
56 return (state->s1 ^ state->s2 ^ state->s3); 59 return (state->s1 ^ state->s2 ^ state->s3);
57} 60}
58 61EXPORT_SYMBOL(prandom32);
59/*
60 * Handle minimum values for seeds
61 */
62static inline u32 __seed(u32 x, u32 m)
63{
64 return (x < m) ? x + m : x;
65}
66 62
67/** 63/**
68 * random32 - pseudo random number generator 64 * random32 - pseudo random number generator
@@ -75,7 +71,7 @@ u32 random32(void)
75{ 71{
76 unsigned long r; 72 unsigned long r;
77 struct rnd_state *state = &get_cpu_var(net_rand_state); 73 struct rnd_state *state = &get_cpu_var(net_rand_state);
78 r = __random32(state); 74 r = prandom32(state);
79 put_cpu_var(state); 75 put_cpu_var(state);
80 return r; 76 return r;
81} 77}
@@ -118,12 +114,12 @@ static int __init random32_init(void)
118 state->s3 = __seed(LCG(state->s2), 15); 114 state->s3 = __seed(LCG(state->s2), 15);
119 115
120 /* "warm it up" */ 116 /* "warm it up" */
121 __random32(state); 117 prandom32(state);
122 __random32(state); 118 prandom32(state);
123 __random32(state); 119 prandom32(state);
124 __random32(state); 120 prandom32(state);
125 __random32(state); 121 prandom32(state);
126 __random32(state); 122 prandom32(state);
127 } 123 }
128 return 0; 124 return 0;
129} 125}
@@ -147,7 +143,7 @@ static int __init random32_reseed(void)
147 state->s3 = __seed(seeds[2], 15); 143 state->s3 = __seed(seeds[2], 15);
148 144
149 /* mix it in */ 145 /* mix it in */
150 __random32(state); 146 prandom32(state);
151 } 147 }
152 return 0; 148 return 0;
153} 149}