From: Keith Packard <keithp@keithp.com>
Date: Wed, 18 Mar 2015 07:17:00 +0000 (-0700)
Subject: hwrng: core - allow perfect entropy from hardware devices
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=506bf0c0464ace57169aadcf02ae397999c57bdd;p=linux-beck.git

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 83161dde53ee..571ef61f8ea9 100644
--- 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);