hwrng: core - allow perfect entropy from hardware devices

Hardware random number quality is measured from 0 (no entropy) to 1024
(perfect entropy). Allow hardware devices to assert the full range by
truncating the device-provided value at 1024 instead of 1023.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 83161dd..571ef61 100644 (file)
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -179,7 +179,8 @@ skip_init:
        add_early_randomness(rng);
 
        current_quality = rng->quality ? : default_quality;
-       current_quality &= 1023;
+       if (current_quality > 1024)
+               current_quality = 1024;
 
        if (current_quality == 0 && hwrng_fill)
                kthread_stop(hwrng_fill);