From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1005AC433EF for ; Mon, 16 May 2022 21:28:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347038AbiEPV2I (ORCPT ); Mon, 16 May 2022 17:28:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51198 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231365AbiEPV2D (ORCPT ); Mon, 16 May 2022 17:28:03 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0DF83EBA8 for ; Mon, 16 May 2022 14:28:02 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4B6556155D for ; Mon, 16 May 2022 21:28:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F128C385AA; Mon, 16 May 2022 21:28:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1652736481; bh=EM6ZQkiQKgpAaDYaA6WjPhnZvN0fVUJjX1XitUtMIs8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ZncUOfR5ydNppphNM7bCyHaeeVtoa/cDcINUcafTV2G5pjni+bwaDQQd96t7ZAIml DJqkX8XWxDIoclFzgJk6S7FBgdujsfRsJW/ADQ8+B+NoCfPLUx4HTrR3p67q0PWa4O sIF+9ZBSf3FfS7U9tYVzcJY4KBnC9vyPhGkO5++Q= Date: Mon, 16 May 2022 14:28:00 -0700 From: Andrew Morton To: "Jason A. Donenfeld" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Theodore Ts'o Subject: Re: [PATCH] random: move randomize_page() into mm where it belongs Message-Id: <20220516142800.4730a41ec1498d5e3d7863c0@linux-foundation.org> In-Reply-To: <20220514120556.363559-1-Jason@zx2c4.com> References: <20220514120556.363559-1-Jason@zx2c4.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 14 May 2022 14:05:56 +0200 "Jason A. Donenfeld" wrote: > randomize_page is an mm function. It is documented like one. It contains > the history of one. It has the naming convention of one. It looks > just like another very similar function in mm, randomize_stack_top(). > And it has always been maintained and updated by mm people. There is no > need for it to be in random.c. In the "which shape does not look like > the other ones" test, pointing to randomize_page() is correct. > > So move randomize_page() into mm/util.c, right next to the similar > randomize_stack_top() function. > > This commit contains no actual code changes. hm, does it make sense? Probably randomize_page() (which used to be called randomize_range()) should have been called randomize_address(). Is it an MM function then? Not really - it's simply an application of the random number generator. So I think it's more a random thing than an MM thing. > --- a/mm/util.c > +++ b/mm/util.c > @@ -343,6 +343,38 @@ unsigned long randomize_stack_top(unsigned long stack_top) > #endif > } > > +/** > + * randomize_page - Generate a random, page aligned address The patch assumes that drivers/char/random.o is always built into vmlinux, which appears to be the case. If some space-conscious person goes and makes random.o build-time optional then they'll need to make the appropriate adjustments in util.c. I see no problems with this.