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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 3F484C433DF for ; Wed, 24 Jun 2020 17:22:49 +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 08C2B2078D for ; Wed, 24 Jun 2020 17:22:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HTew5hNr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 08C2B2078D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35196 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jo96m-0008BO-AY for qemu-devel@archiver.kernel.org; Wed, 24 Jun 2020 13:22:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58446) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jo8oT-0004k7-Bt for qemu-devel@nongnu.org; Wed, 24 Jun 2020 13:03:53 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:32538 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jo8oR-0005Zj-50 for qemu-devel@nongnu.org; Wed, 24 Jun 2020 13:03:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593018230; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SLEatqVNlkcqB3fjCKJjp7utMUgjc7lJx9oB9/HGCF8=; b=HTew5hNrOsbSFY7vc3wMX3GVpyGjjM5L1fdoZX+cwqkU6ea2/kaGio0QHSh1I2DIbsSZ1Y UVk0pK4CZgVmXltg8Uz1LnWmSPtaKqXi4umlZ5Xm85zD2nL35zA4A9fw7fIIw+0MR52aph 45ZEVOO1ZokoF96o4aLBlY4BbpWlDMQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-148-9OarDQkzNuiaOuEIGSRt_g-1; Wed, 24 Jun 2020 13:03:47 -0400 X-MC-Unique: 9OarDQkzNuiaOuEIGSRt_g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0E853805EE1; Wed, 24 Jun 2020 17:03:47 +0000 (UTC) Received: from [10.36.114.197] (ovpn-114-197.ams2.redhat.com [10.36.114.197]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 470D410190DF; Wed, 24 Jun 2020 17:03:36 +0000 (UTC) Subject: Re: [PATCH v2 1/2] qom: Introduce object_property_try_add_child() To: Paolo Bonzini , eric.auger.pro@gmail.com, qemu-devel@nongnu.org, berrange@redhat.com, ehabkost@redhat.com, armbru@redhat.com References: <20200624124301.7112-1-eric.auger@redhat.com> <20200624124301.7112-2-eric.auger@redhat.com> <1a144355-27bd-a26f-752e-00c2751d3a1f@redhat.com> <2bf606dd-4ed3-ec65-3dc2-72089bc7cef5@redhat.com> <430f6b32-8456-ac1d-72b3-85e0e59ae9b5@redhat.com> <3f1aafa9-aedb-b067-7eb7-5d9bc7ce49d1@redhat.com> From: Auger Eric Message-ID: <2aeae131-38e3-7106-0175-b38b7c50f70d@redhat.com> Date: Wed, 24 Jun 2020 19:03:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <3f1aafa9-aedb-b067-7eb7-5d9bc7ce49d1@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=eric.auger@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/24 03:27:53 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Paolo, On 6/24/20 6:16 PM, Paolo Bonzini wrote: > On 24/06/20 18:02, Auger Eric wrote: >> Hi Paolo, >> >> On 6/24/20 4:17 PM, Auger Eric wrote: >>> Hi Paolo, >>> >>> On 6/24/20 4:12 PM, Paolo Bonzini wrote: >>>> On 24/06/20 14:43, Eric Auger wrote: >>>>> + op = object_property_try_add(obj, name, type, object_get_child_property, >>>>> + NULL, object_finalize_child_property, >>>>> + child, errp); >>>>> + if (!op) { >>>>> + goto out; >>>>> + } >>>>> op->resolve = object_resolve_child_property; >>>>> +out: >>>>> object_ref(child); >>>>> child->parent = obj; >>>>> return op; >>>> >>>> I think if there's an error you need to return NULL without ref-ing >>>> child, shouldn't you? >>> hum yes you're fully right, the out label is badly placed. >> Looks the unref is done in user_creatable_add_type() in case of error. > > There are two references involved: > > - a reference returned from object_new. user_creatable_add_type() > passes it back to the caller. The object_unref() you found is done > before returning NULL, because in that case nothing is being passed to > the caller > > - a reference stored in child->parent. In case of error that reference > is dropped with object_property_del before returning NULL. > object_property_try_add_child must not store anything in child->parent > in case of error, and therefore it need not add that reference either. > > I hope this is clearer. Yes it helps. Thank you for the clarifications. Eric > > Thanks, > > Paolo > >> Isn't it the corresponding one? Anyway I think it is better to avoid >> getting the ref here as you suggest (and also free type) and don't unref >> in user_creatable_add_type. >> >> Thanks >> >> Eric >>>> >>>> You can then add another test that object_property_add_child succeeds >>>> after object_property_try_add_child fails. >>> OK >>> >>> Thanks >>> >>> Eric >>>> >>>> Paolo >>>> >> > >