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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 98EDFC54E41 for ; Wed, 28 Feb 2024 09:18:34 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rfG4Q-0002N0-Cy; Wed, 28 Feb 2024 04:17:46 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rfG4N-0002Lp-T3 for qemu-devel@nongnu.org; Wed, 28 Feb 2024 04:17:44 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rfG4M-0002k4-Gj for qemu-devel@nongnu.org; Wed, 28 Feb 2024 04:17:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709111861; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0ljxYO9zkFv3rjCkGwgPT120Y6DvwIv2Nzc+Adzd6Pw=; b=FzqaSthxT+WTRBb1Pwa/ZvK8se2XsrZ7okkbxx2yCi8WszmlO6CXLAPe7ZDDUA8y5ucuSv GUpsTsxLtV/G1UBic3sNcABoac1XkULTO2AA4G5O4b+pTJ2vSFpuObE1V5vhhIRdvA6KS6 IQlHMjMoYGkNnqGGlCObwNgxhpnQxzA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-230-jm-Ld2OZP2mqjcjukqgLdA-1; Wed, 28 Feb 2024 04:17:36 -0500 X-MC-Unique: jm-Ld2OZP2mqjcjukqgLdA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2C9DB88F9E6; Wed, 28 Feb 2024 09:17:36 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BE5441C060AF; Wed, 28 Feb 2024 09:17:35 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id A7D3621E66F9; Wed, 28 Feb 2024 10:17:34 +0100 (CET) From: Markus Armbruster To: Akihiko Odaki Cc: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , "Michael S. Tsirkin" , Marcel Apfelbaum , Alex Williamson , =?utf-8?Q?C=C3=A9dric?= Le Goater , Paolo Bonzini , Daniel P. =?utf-8?Q?Berrang=C3=A9?= , Eduardo Habkost , Sriram Yagnaraman , Jason Wang , Keith Busch , Klaus Jensen , qemu-devel@nongnu.org, qemu-block@nongnu.org Subject: Re: [PATCH v7 12/16] hw/pci: Replace -1 with UINT32_MAX for romsize In-Reply-To: <20240224-reuse-v7-12-29c14bcb952e@daynix.com> (Akihiko Odaki's message of "Sat, 24 Feb 2024 18:24:44 +0900") References: <20240224-reuse-v7-0-29c14bcb952e@daynix.com> <20240224-reuse-v7-12-29c14bcb952e@daynix.com> Date: Wed, 28 Feb 2024 10:17:34 +0100 Message-ID: <874jdt2bip.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.088, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Akihiko Odaki writes: > romsize is an uint32_t variable. Specifying -1 as an uint32_t value is > obscure way to denote UINT32_MAX. > > Worse, if int is wider than 32-bit, it will change the behavior of a > construct like the following: > romsize = -1; > if (romsize != -1) { > ... > } > > When -1 is assigned to romsize, -1 will be implicitly casted into > uint32_t, resulting in UINT32_MAX. On contrary, when evaluating > romsize != -1, romsize will be casted into int, and it will be a > comparison of UINT32_MAX and -1, and result in false. > > Fix these issues by replacing -1 with UINT32_MAX for statements > involving the variable. Could be viewed as cleanup instead of fix, given how unlikely int wider than 32 bits is. Observation, not a demand :) > Signed-off-by: Akihiko Odaki Reviewed-by: Markus Armbruster