Attachment 317072 Details for Bug 458022 – backported patch

[patch] backported patch

linux-kernel-test.patch (text/plain), 2.23 KB, created by Vitaly Mayatskikh on 2008-09-18 13:04:20 UTC

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Creator: Vitaly Mayatskikh

Created: 2008-09-18 13:04:20 UTC

Size: 2.23 KB

patch

obsolete

>diff --git a/net/core/utils.c b/net/core/utils.c
>index 9c584f8..2f4861e 100644
>--- a/net/core/utils.c
>+++ b/net/core/utils.c
>@@ -79,23 +79,12 @@ static u32 __net_random(struct nrnd_state *state)
> 	return (state->s1 ^ state->s2 ^ state->s3);
> }
> 
>-static void __net_srandom(struct nrnd_state *state, unsigned long s)
>+/*
>+ * Handle minimum values for seeds
>+ */
>+static inline u32 __seed(u32 x, u32 m)
> {
>-	if (s == 0)
>-		s = 1;      /* default seed is 1 */
>-
>-#define LCG(n) (69069 * n)
>-	state->s1 = LCG(s);
>-	state->s2 = LCG(state->s1);
>-	state->s3 = LCG(state->s2);
>-
>-	/* "warm it up" */
>-	__net_random(state);
>-	__net_random(state);
>-	__net_random(state);
>-	__net_random(state);
>-	__net_random(state);
>-	__net_random(state);
>+	return (x < m) ? x + m : x;
> }
> 
> 
>@@ -111,9 +100,15 @@ unsigned long net_random(void)
> 
> void net_srandom(unsigned long entropy)
> {
>-	struct nrnd_state *state = &get_cpu_var(net_rand_state);
>-	__net_srandom(state, state->s1^entropy);
>-	put_cpu_var(state);
>+	int i;
>+	/*
>+	 * No locking on the CPUs, but then somewhat random results are, well,
>+	 * expected.
>+	 */
>+	for_each_possible_cpu (i) {
>+		struct nrnd_state *state = &per_cpu(net_rand_state, i);
>+		state->s1 = __seed(state->s1 ^ entropy, 1);
>+	}
> }
> 
> void __init net_random_init(void)
>@@ -122,7 +117,19 @@ void __init net_random_init(void)
> 
> 	for (i = 0; i < NR_CPUS; i++) {
> 		struct nrnd_state *state = &per_cpu(net_rand_state,i);
>-		__net_srandom(state, i+jiffies);
>+
>+#define LCG(x) ((x) * 69069)   /* super-duper LCG */
>+		state->s1 = __seed(LCG(i + jiffies), 1);
>+		state->s2 = __seed(LCG(state->s1), 7);
>+		state->s3 = __seed(LCG(state->s2), 15);
>+
>+		/* "warm it up" */
>+		__net_random(state);
>+		__net_random(state);
>+		__net_random(state);
>+		__net_random(state);
>+		__net_random(state);
>+		__net_random(state);
> 	}
> }
> 
>@@ -134,7 +141,15 @@ static int net_random_reseed(void)
> 	get_random_bytes(seed, sizeof(seed));
> 	for (i = 0; i < NR_CPUS; i++) {
> 		struct nrnd_state *state = &per_cpu(net_rand_state,i);
>-		__net_srandom(state, seed[i]);
>+		u32 seeds[3];
>+
>+		get_random_bytes(&seeds, sizeof(seeds));
>+		state->s1 = __seed(seeds[0], 1);
>+		state->s2 = __seed(seeds[1], 7);
>+		state->s3 = __seed(seeds[2], 15);
>+
>+		/* mix it in */
>+		__net_random(state);
> 	}
> 	return 0;
> }

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Attachments on bug 458022: 317070 | 317071 | 317072 | 317073 | 317074 | 317075