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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 A3393C433DF for ; Fri, 31 Jul 2020 14:38:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 890792177B for ; Fri, 31 Jul 2020 14:38:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732433AbgGaOiD (ORCPT ); Fri, 31 Jul 2020 10:38:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:38106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728613AbgGaOiC (ORCPT ); Fri, 31 Jul 2020 10:38:02 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F3D5622B3F; Fri, 31 Jul 2020 14:38:01 +0000 (UTC) Date: Fri, 31 Jul 2020 10:38:00 -0400 From: Steven Rostedt To: Andy Shevchenko Cc: Petr Mladek , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Rasmus Villemoes Subject: Re: [PATCH v1 1/3] lib/vsprintf: Replace hidden BUILD_BUG_ON() with static_assert() Message-ID: <20200731103800.36a412eb@oasis.local.home> In-Reply-To: <20200731123145.22357-1-andriy.shevchenko@linux.intel.com> References: <20200731123145.22357-1-andriy.shevchenko@linux.intel.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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' - ' ')); But other than that: Reviewed-by: Steven Rostedt (VMware) -- 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;