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=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 3829EC433E0 for ; Fri, 31 Jul 2020 15:49:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 106A52245C for ; Fri, 31 Jul 2020 15:49:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Pf6LEin+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387553AbgGaPtD (ORCPT ); Fri, 31 Jul 2020 11:49:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726502AbgGaPtC (ORCPT ); Fri, 31 Jul 2020 11:49:02 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA501C061574 for ; Fri, 31 Jul 2020 08:49:02 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id g19so5073152plq.0 for ; Fri, 31 Jul 2020 08:49:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=7k9huCaoUiykFMQi1bHPTD0nkp/If40ytG/MCKguQys=; b=Pf6LEin+GEPsD5iYuHes0bQXHIek1Humy4C2weaxOhAR0mEfnXema8KSd/FejANbXi 6iEQi3UBemtJWC2TEtCAqAERC8yWjCDW/5uIKjaD64T1UEXnkpYNV2DgTwuhCWEiYj9+ eptl7qOXnyN/xlX7fcO8X23ydxT301AsX8e9PHJswfIo1Xp3qqBN2YMCEARIjwRqu5nR nxp2HmUVP5hPLlbJssD3ZKVS6t2QM3g+5JaVI9vwvB4+JA05PizxY0hsDZMDcbhAmbZa XAjqyqmBbAAq7BZmP2lIaOnWkv7TbGyKPWcP+fgKtjQ7lrWBg532ZjXPAd0wmIBf3YO3 XsCw== 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=7k9huCaoUiykFMQi1bHPTD0nkp/If40ytG/MCKguQys=; b=Wz7Sj2G7E7fGX9zPCraytnKtbZHx4JLSFBIJwCod34KcQGB34mTIaEkXCVpgvYDTqx rNDzLwtEt+Vd9YkEe/7kqoSw7/1u7QAfTFAbz49ZHr+B7ft8QCX1xUHfn1RkxkfPjT0/ NmBb2nLHQvc4jEFa6VPlApQuizESQcXGAYlFxoWGO8TP4HK859ALK5mWGGDq4am+PSaY /biTPDOI3P4iGz9s2Xm/VOvEifHN+OZ7vLy+jwDbl/L5Tpbympfbegv0uI9xQXAEQzOn 7ATAILiUTCeDr3j0jXc7YjeMXstV3Mq+NRZP2s3TRYmQ8NKvYweeWoP2IpeX3Dnd/DAS zS4g== X-Gm-Message-State: AOAM533GL8feWbE32er3SGnGIzPs/bGvh+bqO/0QQxF1ely0rfOKhoLi 4MO+oSp2SFjQ/Ovi0pwkrpvpQVSfakTLl8G8M8Y= X-Google-Smtp-Source: ABdhPJzAY8OpzEngMP1t35Gkk80xmy3BANJXADYWSn2JFVXR0WpAt4JLCO/qYzurs/7rBSTqk5ddXCWTACunO9flMHw= X-Received: by 2002:a17:902:4b:: with SMTP id 69mr4324861pla.18.1596210542347; Fri, 31 Jul 2020 08:49:02 -0700 (PDT) MIME-Version: 1.0 References: <20200731123145.22357-1-andriy.shevchenko@linux.intel.com> <20200731103800.36a412eb@oasis.local.home> In-Reply-To: <20200731103800.36a412eb@oasis.local.home> From: Andy Shevchenko Date: Fri, 31 Jul 2020 18:48:45 +0300 Message-ID: Subject: Re: [PATCH v1 1/3] lib/vsprintf: Replace hidden BUILD_BUG_ON() with static_assert() To: Steven Rostedt Cc: Andy Shevchenko , Petr Mladek , Sergey Senozhatsky , Linux Kernel Mailing List , Rasmus Villemoes 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, Jul 31, 2020 at 5:40 PM Steven Rostedt wrote: > > On Fri, 31 Jul 2020 15:31:43 +0300 > Andy Shevchenko wrote: > > > First of all, there is no compile time check for the SMALL > > to be ' ' (0x20, i.e. space). Second, for ZEROPAD the check > > is hidden in the code. > > > > For better maintenance replace BUILD_BUG_ON() with static_assert() > > for ZEROPAD and move it closer to the definition. While at it, > > introduce check for SMALL. > > > > Signed-off-by: Andy Shevchenko > > --- > > lib/vsprintf.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > > index 31a674dd2674..8a8ac7ce0289 100644 > > --- a/lib/vsprintf.c > > +++ b/lib/vsprintf.c > > @@ -381,6 +381,9 @@ int num_to_str(char *buf, int size, unsigned long long num, unsigned int width) > > #define SMALL 32 /* use lowercase in hex (must be 32 == 0x20) */ > > #define SPECIAL 64 /* prefix hex with "0x", octal with "0" */ > > > > +static_assert(ZEROPAD + ' ' == '0'); > > I would have it match the comment above: > > static_assert(ZEROPAD == ('0' - ' ')); Okay, makes sense. Will do in v2. > But other than that: > > Reviewed-by: Steven Rostedt (VMware) Thanks! > > -- Steve > > > +static_assert(SMALL == ' '); > > + > > enum format_type { > > FORMAT_TYPE_NONE, /* Just a string part */ > > FORMAT_TYPE_WIDTH, > > @@ -507,7 +510,7 @@ char *number(char *buf, char *end, unsigned long long num, > > /* zero or space padding */ > > if (!(spec.flags & LEFT)) { > > char c = ' ' + (spec.flags & ZEROPAD); > > - BUILD_BUG_ON(' ' + ZEROPAD != '0'); > > + > > while (--field_width >= 0) { > > if (buf < end) > > *buf = c; > -- With Best Regards, Andy Shevchenko