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 26DCEC87FCF for ; Sat, 9 Aug 2025 14:31:51 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ukkbA-0002fs-HC; Sat, 09 Aug 2025 10:31:04 -0400 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 1ukkae-0002cF-3S for qemu-devel@nongnu.org; Sat, 09 Aug 2025 10:30:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ukkac-0003Sz-8I for qemu-devel@nongnu.org; Sat, 09 Aug 2025 10:30:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754749829; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QtFgom+fibTpSrI/tkRC05vQF1r6SFBFk46gaVK65pI=; b=dFJ3xyrx5Jg1Chdnji9qHf6bKTpEO8K6xskZZD2qKfobTuBfKdqWxeYwrF9KOgeJrOax9J k0dEICmXuBbff+GMyrzz/NFR3Q26hfxSHVNaT2BfH1C8yw5YNEvM/zxBmPvHBr/TQGP1rJ gXKHHlPPEnp6Pj2GAHku5eYaJuuSgxg= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-605-ShBFraTyOymoj3dDrXRBaQ-1; Sat, 09 Aug 2025 10:30:24 -0400 X-MC-Unique: ShBFraTyOymoj3dDrXRBaQ-1 X-Mimecast-MFC-AGG-ID: ShBFraTyOymoj3dDrXRBaQ_1754749822 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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 mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EC72018003FD; Sat, 9 Aug 2025 14:30:20 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.18]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 898FF19560B4; Sat, 9 Aug 2025 14:30:19 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id C97F821E6A27; Sat, 09 Aug 2025 16:30:16 +0200 (CEST) From: Markus Armbruster To: Akihiko Odaki Cc: Markus Armbruster , Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9?= , Arun Menon , qemu-devel@nongnu.org, "Michael S. Tsirkin" , Marcel Apfelbaum , Cornelia Huck , Halil Pasic , Eric Farman , Richard Henderson , David Hildenbrand , Ilya Leoshkevich , Thomas Huth , Christian Borntraeger , Paolo Bonzini , Fam Zheng , Nicholas Piggin , Daniel Henrique Barboza , Harsh Prateek Bora , Alex Williamson , =?utf-8?Q?C=C3=A9dric?= Le Goater , Peter Xu , Fabiano Rosas , Hailiang Zhang , Steve Sistare , qemu-s390x@nongnu.org, qemu-ppc@nongnu.org, Stefan Berger , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Alex =?utf-8?Q?Benn=C3=A9e?= , Dmitry Osipenko , Matthew Rosato Subject: Re: [PATCH v6 23/24] migration: Add error-parameterized function variants in VMSD struct In-Reply-To: (Akihiko Odaki's message of "Sat, 9 Aug 2025 18:53:51 +0900") References: <20250721-propagate_tpm_error-v6-0-fef740e15e17@redhat.com> <20250721-propagate_tpm_error-v6-23-fef740e15e17@redhat.com> <3e9aa703-2805-4ac4-9f10-f4ba71c10c8a@rsg.ci.i.u-tokyo.ac.jp> <9c552525-72fa-4d1e-89a2-b5c0e446935a@rsg.ci.i.u-tokyo.ac.jp> <87fre0ucxu.fsf@pond.sub.org> Date: Sat, 09 Aug 2025 16:30:16 +0200 Message-ID: <87jz3csh3b.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.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, DKIMWL_WL_HIGH=-0.001, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 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: > On 2025/08/09 17:17, Markus Armbruster wrote: >> Almost missed this, sorry. >> Akihiko Odaki writes: >>=20 >>> On 2025/07/21 22:29, Daniel P. Berrang=C3=A9 wrote: [...] >>>> No, please do NOT make these functions void. As that text you quote >>>> says, we want functions to return a value indicating success/failure. >>>> 'void' return is a historical practice we don't want to continue >>>> in QEMU. >>>> >>>> Given that the existing methods all return 'int', we should remain >>>> consistent with the new functions and return 'int', with -1 for >>>> failure, 0 for success, and not use bool. >>> >>> Markus, I'd also like to hear your opinion since you are the maintainer= of the error reporting facility. >> >> I'm with Daniel. >> >> New code should stick to the rules. >> >> Changing existing code from "sticks to the rules" to not requires pretty >> compelling justification. >> >> The other direction is more welcome, but whether the juice is worth the >> squeeze still needs to be decided case by case. > > What do you refer with the rules? The big comment in qapi/error.h starts with a section =3D Rules =3D. > There were three options on the table: bool, int, and void. > > The previous discussion you referred explains why void should be avoided,= and include/qapi/error.h also says void should be avoided. > > There is pre_load() that does not use Error returns int, but now we are a= dding pre_load_errp() that uses Error. > > Then what pre_load_errp() should return: bool or int? I like bool when it's all we need. When we need to return a non-negative int on success, use int and return -1 or a negative error code on failure. Another reason to pick int is local consistency: related functions already use int. Changing working code from int to bool doesn't seem worth the bother. Questions?