From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756934Ab3IETDj (ORCPT ); Thu, 5 Sep 2013 15:03:39 -0400 Received: from imap.thunk.org ([74.207.234.97]:55215 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752581Ab3IETDh (ORCPT ); Thu, 5 Sep 2013 15:03:37 -0400 Date: Thu, 5 Sep 2013 15:03:34 -0400 From: "Theodore Ts'o" To: Prarit Bhargava Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] random, Add user configurable get_bytes_random() Message-ID: <20130905190334.GC23661@thunk.org> Mail-Followup-To: Theodore Ts'o , Prarit Bhargava , linux-kernel@vger.kernel.org References: <1378383524-27983-1-git-send-email-prarit@redhat.com> <20130905144818.GA23661@thunk.org> <52289E6C.8090301@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52289E6C.8090301@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 05, 2013 at 11:08:28AM -0400, Prarit Bhargava wrote: > > The issue isn't userspace /dev/random as much as it is the use of > get_random_bytes() through out the kernel. Switching to get_random_bytes_arch() > is a search'n'replace on the entire kernel. If a user wants the faster random > HW generator why shouldn't they be able to use it by default? Where is the speed of the random number generator a bottleneck? In general, adding knobs when users can make what might be potentially the wrong chance is very dangerous. There is a reason why there aren't convenient knobs to allow users to select the use of the MD4 checksum, "because it might be faster, why shouldn't the user be allowed to shoot themselves in the foot"? - Ted