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=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED 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 2866EC43381 for ; Fri, 22 Mar 2019 16:21:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E76ED2190A for ; Fri, 22 Mar 2019 16:21:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="yXeM6mBW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727236AbfCVQVW (ORCPT ); Fri, 22 Mar 2019 12:21:22 -0400 Received: from mail-io1-f67.google.com ([209.85.166.67]:43568 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726801AbfCVQVW (ORCPT ); Fri, 22 Mar 2019 12:21:22 -0400 Received: by mail-io1-f67.google.com with SMTP id x3so2157365iol.10 for ; Fri, 22 Mar 2019 09:21:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=FinR+IjhZDJgPonC4fG9bQ8oToE745baJij2yjHIuSw=; b=yXeM6mBWjCkKz0G3Jx7TkTFp6qEugUDgoTTzWcZqjmmQo1guYtvaNro3m8PQ5yIyV6 j8GRm3pcaDDCTlo+j1rMgWFzm7D36KGzN+8UkRhvRHwnDyVgSCgO+ar33pCFtlWg9FZz N+uL2cVTBLgpFhI43ozMWZX+wA9xS1NzY/7kWC3HaBc2UDCIoPQZKq8uwTcipJ7+yqEh 08mTJ8v5+2uSRzDgF3p2P0rydcmFtRuW5khFfHuhScc1QMKEas+NcBaxzAlhnrryGt/3 eaQjuJR+qHOXDq5jZUc0pNfTukYC9YumD4eAkENBwNJayqZT8ynPYWUF4RcqVroniE+U JkMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=FinR+IjhZDJgPonC4fG9bQ8oToE745baJij2yjHIuSw=; b=UKZ4aB//teqRoXe7NYla4LX/dFenn2/hk1L899v5XZrdzr2wwghlL1yrWnVC3T/jWR qBOsT4yfD6cXdIVqVhIMvuwVj6i+qC3kEmGYiaIcjkqPyjKGZfHZnZd7Huti1gzqPPCb h5sXbICJhfQTQKJAOkjMQUTe6TJEs9Ps7xsit3mhbhsAbni/U7OIu7COj8Y1wcgVa1re H0M6yHLW+cll1WCZHuQuE9viSWJYesAl4Wh7WC9Bg+NUc22VQoelOfViQjAj56mlSVFj 0w0WBydvoNrapqtQS2QindqroPxN0N/VMD/8Hrcb1v30s58bLCwlNE3rktdOfQaztVGl T1xg== X-Gm-Message-State: APjAAAWxwqxKAXr1aq/B8sOYZdKTMbCg6roRh8YoFcd1SriyWwN9oZJu vFyRmiIYBjc0jS7fV4tzvOBuOpXSN8XXMfl0ABPsXw== X-Google-Smtp-Source: APXvYqyYvUNkkH7/kVxFEBmTPdnSzEM26yKlFgHZNF9RUgA357LvIA2jIyluI9ZY/Z8xlnqX1yMfavwoKVA7Vxf1Fk0= X-Received: by 2002:a5d:8b41:: with SMTP id c1mr7546985iot.173.1553271681269; Fri, 22 Mar 2019 09:21:21 -0700 (PDT) MIME-Version: 1.0 References: <5ef0cab4dee128058a43f43c723c13924662e80d.camel@perches.com> <20190322124331.s5iu4ontsakv7he5@gondor.apana.org.au> In-Reply-To: From: Ard Biesheuvel Date: Fri, 22 Mar 2019 17:21:10 +0100 Message-ID: Subject: Re: [possible PATCH] crypto: sahara - Use #ifdef DEBUG not IS_ENABLED(DEBUG) To: Joe Perches Cc: Herbert Xu , "David S. Miller" , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 22 Mar 2019 at 16:07, Joe Perches wrote: > > On Fri, 2019-03-22 at 15:29 +0100, Ard Biesheuvel wrote: > > On Fri, 22 Mar 2019 at 13:43, Herbert Xu wrote: > > > On Thu, Mar 07, 2019 at 04:15:55PM -0800, Joe Perches wrote: > > > > Normal use of IS_ENABLED is with a CONFIG_ and > > > > there is no -DDEBUG in the Makefile here. > > > > > > > > Replace the IS_ENABLED(DEBUG) with #ifdef DEBUG/#endif > > > > blocks. > > > > > > > > Miscellanea: > > > > > > > > o Move the sahara_state array into the function that uses it. > > > > > > > > Signed-off-by: Joe Perches > > > > --- > > > > drivers/crypto/sahara.c | 20 +++++++++----------- > > > > 1 file changed, 9 insertions(+), 11 deletions(-) > > > > > > Even if this is correct this is way too ugly. The original code > > > at least compiled everything regardless of macros. Your new code > > > won't detect compile errors in debugging code unless debugging is > > > enabled. > > > > > > > What's wrong with IS_ENABLED(DEBUG) anyway? It may not be 'normal use' > > but it works fine. > > drivers/crypto/sahara.c is the only user in the kernel tree. > So only it's abnormal use. I rather like the concept actually. > > IS_ENABLED is almost exclusively used with CONFIG_ symbols > and it could be useful to require it to be used with CONFIG_ > symbols and use some other similar mechanism for DEBUG use. > > Maybe just adding a global #define in kernel.h like > > #define IS_DEBUG_ENABLED IS_ENABLED(DEBUG) > __is_defined(DEBUG) seems to be the most appropriate here. I don't feel strongly about whether we or not should wrap it in another macro. > to isolate this in one place might be better. > > A good thing about using IS_ENABLED or the suggested IS_DEBUG_ENABLED > would be that least gcc 5+ seems to automatically elide the uses of any > unreferenced static const char * arrays like the sahara_state uses here. > Yes, that is kind of the point. If you use #ifdef, the compiler will complain about unused static variables in this case. > (I don't have gcc4 anymore so I couldn't check that version) > > So using 'if (IS_DEBUG_ENABLED)' could simplify some existing code like > the many uses of > > #ifdef DEBUG > ... > #endif > > or equivalent > > My vote would be to use __is_defined(DEBUG) in place, but if others prefer wrapping it in a macro, that is also fine with me.