linux-kernel - [PATCH] randomize_range: use random long instead of int

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Date:	Mon, 25 Jul 2016 11:25:41 -0700
From:	william.c.roberts@...el.com
To:	linux-mm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	linux@....linux.org.uk, akpm@...ux-foundation.org,
	keescook@...omium.org, tytso@....edu, arnd@...db.de,
	gregkh@...uxfoundation.org, catalin.marinas@....com,
	will.deacon@....com, ralf@...ux-mips.org, benh@...nel.crashing.org,
	paulus@...ba.org, mpe@...erman.id.au, davem@...emloft.net,
	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	x86@...nel.org, viro@...iv.linux.org.uk, nnk@...gle.com,
	jeffv@...gle.com, salyzyn@...roid.com, dcashman@...roid.com,
	William Roberts <william.c.roberts@...el.com>
Subject: [PATCH] randomize_range: use random long instead of int

From: William Roberts <william.c.roberts@...el.com>

Use a long when generating the random range rather than
an int. This will produce better random distributions as
well as matching all the types at hand.

Signed-off-by: William Roberts <william.c.roberts@...el.com>
---
 drivers/char/random.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 0158d3b..bbf11b5 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1837,7 +1837,8 @@ randomize_range(unsigned long start, unsigned long end, unsigned long len)
 
 	if (end <= start + len)
 		return 0;
-	return PAGE_ALIGN(get_random_int() % range + start);
+
+	return PAGE_ALIGN(get_random_long() % range + start);
 }
 
 /* Interface for in-kernel drivers of true hardware RNGs.
-- 
1.9.1