[PATCH next 6/7] random32: prandom_seed_state() use all 64 bits of the seed

[David Laight]

Use the high 32bits to initialise s3 and s4 rather than reducing
the value to 32 bits.
Simplify the avoidance of values near zero by just setting a bit.
Keep the '<< 10' so that bits 0 and 32-35 get used.

Signed-off-by: David Laight <david.laight.linux@xxxxxxxxx>
---
 lib/random32.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/random32.c b/lib/random32.c
index 83776345adda..1d6468045267 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -133,11 +133,12 @@ EXPORT_SYMBOL(prandom_seed_full_state);
 
 void prandom_seed_state(struct rnd_state *state, u64 seed)
 {
-	u32 i = ((seed >> 32) ^ (seed << 10) ^ seed) & 0xffffffffUL;
+	seed ^= seed << 10;
 
-	state->s1 = __seed(i,   2U);
-	state->s2 = __seed(i,   8U);
-	state->s3 = __seed(i,  16U);
-	state->s4 = __seed(i, 128U);
+	/* The values must not be near zero. */
+	state->s1 = seed | 0x100;
+	state->s2 = seed | 0x200;
+	state->s3 = (seed >> 32) | 0x100;
+	state->s4 = (seed >> 32) | 0x200;
 }
 EXPORT_SYMBOL(prandom_seed_state);
-- 
2.39.5