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 X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83BEDC07E95 for ; Mon, 19 Jul 2021 18:27:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67E1860FDB for ; Mon, 19 Jul 2021 18:27:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382682AbhGSRjr (ORCPT ); Mon, 19 Jul 2021 13:39:47 -0400 Received: from gate.crashing.org ([63.228.1.57]:36742 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354624AbhGSQaW (ORCPT ); Mon, 19 Jul 2021 12:30:22 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 16JH4N2o028857; Mon, 19 Jul 2021 12:04:23 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 16JH4Mln028856; Mon, 19 Jul 2021 12:04:22 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 19 Jul 2021 12:04:22 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Salah Triki , herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org, paulus@samba.org, linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, davem@davemloft.net Subject: Re: [PATCH] replace if with min Message-ID: <20210719170422.GO1583@gate.crashing.org> References: <20210712204546.GA1492390@pc> <20210719181205.Horde.xU8C00MIRgjqhZQ3-RrANw8@messagerie.c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210719181205.Horde.xU8C00MIRgjqhZQ3-RrANw8@messagerie.c-s.fr> User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 19, 2021 at 06:12:05PM +0200, Christophe Leroy wrote: > Salah Triki a écrit : > >Replace if with min in order to make code more clean. > >--- a/drivers/crypto/nx/nx-842.c > >+++ b/drivers/crypto/nx/nx-842.c > >@@ -134,8 +134,7 @@ EXPORT_SYMBOL_GPL(nx842_crypto_exit); > > static void check_constraints(struct nx842_constraints *c) > > { > > /* limit maximum, to always have enough bounce buffer to decompress > > */ > >- if (c->maximum > BOUNCE_BUFFER_SIZE) > >- c->maximum = BOUNCE_BUFFER_SIZE; > >+ c->maximum = min(c->maximum, BOUNCE_BUFFER_SIZE); > > For me the code is less clear with this change, and in addition it > slightly changes the behaviour. Before, the write was done only when > the value was changing. Now you rewrite the value always, even when it > doesn't change. In both cases the compiler can decide to either write it more often than strictly needed, depending on what it thinks best (and it usually has better estimates than the programmer). The behaviour is identical (and the generated machine code is as well, in my testing). The field name "maximum" is not the best choice, which makes the code read a bit funny ("the min of max"), but the comment makes things pretty clear. Segher