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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 362DCC31E40 for ; Sat, 3 Aug 2019 18:36:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF0CA206A2 for ; Sat, 3 Aug 2019 18:36:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="iYNYmAfY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728774AbfHCSgn (ORCPT ); Sat, 3 Aug 2019 14:36:43 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:45151 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728198AbfHCSgn (ORCPT ); Sat, 3 Aug 2019 14:36:43 -0400 Received: by mail-lj1-f193.google.com with SMTP id m23so75717631lje.12 for ; Sat, 03 Aug 2019 11:36:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=NSi9TsGQZaVw6ZnB5I+qwD8eQNLA90Rl9Pl0pGBoFKk=; b=iYNYmAfYPo91w0uTmZHV0nLr+KnMSZUDVJzS17n/JwAllP8QqUQoSrEqhOD/I+nyUs zd0WtPlRZLpypUIjAXJJf+oKQp0Xh6EyOhP3js0LQopfrZ6ZyJ/EKpOCuidyeNpzYvTY AV7SiK6moveh3mhwpLmTjFqUxs3Iunh2bE8qbimoTsqOci1qrVoaqjGSJ2hNiK4l6sNP Be52NpI0Pqx7HK3lS+reLkiTiI35Und7ven7XSuHgpvQ/eK9yCfjqdmdcGRge/IhopLA BRMSHwtRpzyMrG8SHZWolDuUr2BApfhz9RzRpQ3bx5GceIu9MkeNyCMF67VsFEYbUuFL 51OA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=NSi9TsGQZaVw6ZnB5I+qwD8eQNLA90Rl9Pl0pGBoFKk=; b=dtDCHawCqT92csTzaL8DzUBMSauKyWr+aqUO5pEpDzvYzqM9M+TlsXr0V8QjdNCGko aj01BDnOOGVdGDzhNxRrzr4Qg2fv3tkQYkd1hKQiVD4slY9O2L6Q5Qh6U0QOgryRPzWe t5U7saEpTUEeQdiQVsgsNAWm7qfAPyhA2oIhnzW2Gwqc2PeU1LKUmj1PwFRiO3R7alF3 /n6ejaGcD9JUkVWq1aK444liFshIRXSjBiStHH2+n+OewPzoJjYvRRftDQ85dmQLmbZL prqdq1LRE2lHINZnb8J49yhL2EwWbU2Q93ynEaeqMoyvTXNvEHz958WPlor9S2NJW4bs 4Ktg== X-Gm-Message-State: APjAAAXDOf+SLBRn1qcQjLXp+wHXdCbeEzJyUbN/L8Gj8YwlVIeWmM5H huHMmuSQtelmqtRVCs6Hn2o= X-Google-Smtp-Source: APXvYqyXgo8Xs/B2nD15LYQVjuKG9rBD/Oc+6YQ8mAiuxTFnXGfk4KTb5tOrOsvIfmjT6KEbQbt3Lw== X-Received: by 2002:a2e:8ed2:: with SMTP id e18mr33045635ljl.235.1564857401548; Sat, 03 Aug 2019 11:36:41 -0700 (PDT) Received: from rikard (h-158-174-186-115.NA.cust.bahnhof.se. [158.174.186.115]) by smtp.gmail.com with ESMTPSA id n24sm15971745ljc.25.2019.08.03.11.36.39 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Sat, 03 Aug 2019 11:36:40 -0700 (PDT) From: Rikard Falkeborn X-Google-Original-From: Rikard Falkeborn Date: Sat, 3 Aug 2019 20:36:37 +0200 To: Masahiro Yamada Cc: Rikard Falkeborn , Joe Perches , Andrew Morton , Johannes Berg , Linux Kernel Mailing List Subject: Re: [PATCH] linux/bits.h: Add compile time sanity check of GENMASK inputs Message-ID: <20190803183637.GA831@rikard> References: <0306bec0ec270b01b09441da3200252396abed27.camel@perches.com> <20190731190309.19909-1-rikard.falkeborn@gmail.com> <47d29791addc075431737aff4b64531a668d4c1b.camel@perches.com> <2b782cf609330f53b6ecc5b75a8a4b49898483eb.camel@perches.com> <20190802181853.GA809@rikard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 03, 2019 at 12:12:46PM +0900, Masahiro Yamada wrote: > On Sat, Aug 3, 2019 at 12:03 PM Masahiro Yamada > wrote: > > > > > BTW, v2 is already inconsistent. > > If you wanted GENMASK_INPUT_CHECK() to return 'unsigned long',, > > you would have to cast (low) > (high) as well: > > > > (unsigned long)((low) > (high)), UL(0)))) > > > > This is totally redundant, and weird. > > I take back this comment. > You added (unsigned long) to the beginning of this macro. > So, the type is consistent, but I believe all casts should be removed. Maybe you're right. BUILD_BUG_ON_ZERO returns size_t regardless of inputs. I was worried that on some platform, size_t would be larger than unsigned long (as far as I could see, the standard does not give any guarantees), and thus all of a sudden GENMASK would be 8 bytes instead of 4, but perhaps that is not a problem?