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=ham 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 0EA7EC64980 for ; Mon, 19 Jul 2021 17:08:18 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CAECC60FE9 for ; Mon, 19 Jul 2021 17:08:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CAECC60FE9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4GT7b32m0Fz3bft for ; Tue, 20 Jul 2021 03:08:15 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 4GT7ZZ5JHrz2yP2 for ; Tue, 20 Jul 2021 03:07:50 +1000 (AEST) 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 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 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: herbert@gondor.apana.org.au, Salah Triki , linux-kernel@vger.kernel.org, paulus@samba.org, linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, davem@davemloft.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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