From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755482AbcGZCSv (ORCPT ); Mon, 25 Jul 2016 22:18:51 -0400 Received: from pmta2.delivery5.ore.mailhop.org ([54.186.218.12]:63075 "EHLO pmta2.delivery5.ore.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755384AbcGZCSg (ORCPT ); Mon, 25 Jul 2016 22:18:36 -0400 X-MHO-User: 68e05b06-52d7-11e6-8929-8ded99d5e9d7 X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 74.99.77.15 X-Mail-Handler: DuoCircle Outbound SMTP X-DKIM: OpenDKIM Filter v2.6.8 io EBF648001D Date: Tue, 26 Jul 2016 02:18:30 +0000 From: Jason Cooper To: william.c.roberts@intel.com Cc: linux-mm@vger.kernel.org, linux-kernel@vger.kernel.org, linux@arm.linux.org.uk, akpm@linux-foundation.org, keescook@chromium.org, tytso@mit.edu, arnd@arndb.de, gregkh@linuxfoundation.org, catalin.marinas@arm.com, will.deacon@arm.com, ralf@linux-mips.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk, nnk@google.com, jeffv@google.com, salyzyn@android.com, dcashman@android.com Subject: Re: [PATCH] randomize_range: use random long instead of int Message-ID: <20160726021830.GC4541@io.lakedaemon.net> References: <1469471141-25669-1-git-send-email-william.c.roberts@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1469471141-25669-1-git-send-email-william.c.roberts@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi William, Kees, On Mon, Jul 25, 2016 at 11:25:41AM -0700, william.c.roberts@intel.com wrote: > From: William Roberts > > 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 > --- > drivers/char/random.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) Upon further review, I think we should dig into this a little bit deeper. Standby, I'll post an RFC series shortly. thx, Jason. > 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 >