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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, 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 54753C433B4 for ; Fri, 7 May 2021 16:02:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 805D861041 for ; Fri, 7 May 2021 16:02:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 805D861041 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34856 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lf2vu-0007hW-6O for qemu-devel@archiver.kernel.org; Fri, 07 May 2021 12:02:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56424) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lf2t5-0006En-V6 for qemu-devel@nongnu.org; Fri, 07 May 2021 11:59:40 -0400 Received: from mail-pj1-x1033.google.com ([2607:f8b0:4864:20::1033]:43586) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lf2ss-00064V-J1 for qemu-devel@nongnu.org; Fri, 07 May 2021 11:59:33 -0400 Received: by mail-pj1-x1033.google.com with SMTP id cl24-20020a17090af698b0290157efd14899so5580127pjb.2 for ; Fri, 07 May 2021 08:59:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=d7jv4zOm3ReTIeRrS+13gTyx4T6znAQLdZT0jfWV9Mg=; b=BvksK0Ks0r5FKrZiEpT3wVjPf/32vZ6B2Odz7lMbkA2XTJN8E2ZBUuc2/fcZfc6fhD ujoO/tQI8k9XoeShNHq1E2ZWYbhrp1psPBsnuNy7WE6v/GHbATuMhFwX7tdH6yhUYN7d O6wXZ7ipk5/b2aOUqY9IVuT/LkYWieZtr3eAj6SdURLzQ3qccgO382dCX7br21z0hNlm n0zCqFKL0j+mTiLn4WxdeVbD3kAuAPORvbqDs7SR8rRWLwXsSe9c7obFnf2dwHCgG26M 6ruxC+653+2tSXV/u1hfEiAX2HBDFhvdm2BC3ZoDRGsEv1lwkWZN7V/xLWZjy4ZBlsSk zaQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=d7jv4zOm3ReTIeRrS+13gTyx4T6znAQLdZT0jfWV9Mg=; b=Gzwad50xHzWTIcJFLMFWoutrn0Yg/sVeBFFBp6Km1vZu6ej2ifdbpW3pqnODUN4nfW UBbn3ZPcR1lpoFuZq0FWbG2YU+gwIAh8V0Tv3MHWnSFaIMawqgZtpNanyZiUGM96ciC/ +QHnzVgyO9AcK9rHIgvq5PkAYOGJ4r7m6sM1cEGVOV/cx4wjmOJW7Anhky7cXmj8aiz4 /1D1hqrPn+5Hl+HCMKT7KUHvBN5nfIafdJEWkfd9ZteClceONaxi+3YllX9wjsKayc80 wsQhT1aQxcY9gfC4TSPoj1gVL/hu6L1986lIoA7UPfpAh0I4u+GkDAQtiJAux6oItbYc bp5Q== X-Gm-Message-State: AOAM5318oa364xW1tJZmLTM2xqYrxvNp+n5W/ONaKVpfPlkLKgnuBpAo Dbs4lneEbHFe40ar8mlc1VeSug== X-Google-Smtp-Source: ABdhPJwy3gQYbPBZlaz5S5bNPH4VouquSPnEbMp9T3ml1AGB5vbVtXY+gEMtUS8o2nKFdrJyXamn+g== X-Received: by 2002:a17:902:e5cb:b029:ed:64d5:afee with SMTP id u11-20020a170902e5cbb02900ed64d5afeemr10517733plf.41.1620403160865; Fri, 07 May 2021 08:59:20 -0700 (PDT) Received: from [192.168.1.11] ([71.212.144.24]) by smtp.gmail.com with ESMTPSA id a129sm5299173pfa.36.2021.05.07.08.59.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 07 May 2021 08:59:20 -0700 (PDT) Subject: Re: [PATCH 07/23] hw/block/nvme: Use definition to avoid dynamic stack allocation To: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-devel@nongnu.org References: <20210505211047.1496765-1-philmd@redhat.com> <20210505211047.1496765-8-philmd@redhat.com> From: Richard Henderson Message-ID: <0161c3a7-c3e8-d69b-8c60-fc63927e34af@linaro.org> Date: Fri, 7 May 2021 08:59:18 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210505211047.1496765-8-philmd@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::1033; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x1033.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , qemu-block@nongnu.org, Max Reitz , Klaus Jensen , qemu-ppc@nongnu.org, Gerd Hoffmann , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , Keith Busch , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/5/21 2:10 PM, Philippe Mathieu-Daudé wrote: > The compiler isn't clever enough to figure 'SEG_CHUNK_SIZE' is > a constant! Help it by using a definitions instead. This isn't about being clever or not, it's semantics. In C++, "const int" is a proper constant, but in C it is a variable with a constant value. Thus the use of the symbol in the array bounds is, by definition, variable. > - const int SEG_CHUNK_SIZE = 256; > +#define SEG_CHUNK_SIZE 256 enum { SEG_CHUNK_SIZE = 256 }; would retain the function scope for the symbol, if that's desirable. r~