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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95A11C433F5 for ; Mon, 27 Sep 2021 10:37:59 +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 92B0D6103B for ; Mon, 27 Sep 2021 10:37:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 92B0D6103B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=greensocs.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:42994 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mUo1F-0006Ps-Ee for qemu-devel@archiver.kernel.org; Mon, 27 Sep 2021 06:37:57 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37154) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mUnxE-0003ky-8v; Mon, 27 Sep 2021 06:33:48 -0400 Received: from beetle.greensocs.com ([5.135.226.135]:57252) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mUnx7-0003sg-Px; Mon, 27 Sep 2021 06:33:47 -0400 Received: from [192.168.15.164] (unknown [195.68.53.70]) by beetle.greensocs.com (Postfix) with ESMTPSA id 7D0AB20777; Mon, 27 Sep 2021 10:33:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=greensocs.com; s=mail; t=1632738814; 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=db5qkmM+2vNNgmbl2hoTf61puFV6WIfM7ENDnHPGMpQ=; b=WjqsSm8DaebBVLYDfJvo9iIHUfIv2+tx08XhHxzTRSY+ClfgCrqVgBUT1l8CsewZY4WkI3 lm9A3QzIYwESzVfEnjcgQTLiq9WsjU3qbk55ul3P/Sf94uA5/q5PbzN4cRbvD7w/Sh3JP7 KiGxtZopyLX0AUdCIpw7UsrLeBM8qxc= Message-ID: <90412958-721b-4ae8-0177-3ae6af8394af@greensocs.com> Date: Mon, 27 Sep 2021 12:33:32 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 Subject: Re: [PATCH 06/11] qdev: Add Error parameter to qdev_set_id() Content-Language: en-US-large To: Vladimir Sementsov-Ogievskiy , Kevin Wolf , qemu-devel@nongnu.org References: <20210924090427.9218-1-kwolf@redhat.com> <20210924090427.9218-7-kwolf@redhat.com> <7b9afc35-af95-ad21-6296-7e112ada9c87@virtuozzo.com> From: Damien Hedde In-Reply-To: <7b9afc35-af95-ad21-6296-7e112ada9c87@virtuozzo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=5.135.226.135; envelope-from=damien.hedde@greensocs.com; helo=beetle.greensocs.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 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=-0.478, SPF_HELO_NONE=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pkrempa@redhat.com, berrange@redhat.com, ehabkost@redhat.com, qemu-block@nongnu.org, libvir-list@redhat.com, armbru@redhat.com, its@irrelevant.dk, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Kevin, I proposed a very similar patch in our rfc series because we needed some of the cleaning you do here. https://lists.gnu.org/archive/html/qemu-devel/2021-09/msg05679.html I've added a bit of doc for the function, feel free to take it if you want. On 9/24/21 16:09, Vladimir Sementsov-Ogievskiy wrote: > 24.09.2021 12:04, Kevin Wolf wrote: >> object_property_add_child() fails (with &error_abort) if an object with >> the same name already exists. As long as QemuOpts is in use for -device >> and device_add, it catches duplicate IDs before qdev_set_id() is even >> called. However, for enabling non-QemuOpts code paths, we need to make >> sure that the condition doesn't cause a crash, but fails gracefully. >> >> Signed-off-by: Kevin Wolf >> --- >>   include/monitor/qdev.h      |  2 +- >>   hw/xen/xen-legacy-backend.c |  3 ++- >>   softmmu/qdev-monitor.c      | 16 ++++++++++------ >>   3 files changed, 13 insertions(+), 8 deletions(-) >> >> diff --git a/include/monitor/qdev.h b/include/monitor/qdev.h >> index 389287eb44..7961308c75 100644 >> --- a/include/monitor/qdev.h >> +++ b/include/monitor/qdev.h >> @@ -9,6 +9,6 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, >> Error **errp); >>   int qdev_device_help(QemuOpts *opts); >>   DeviceState *qdev_device_add(QemuOpts *opts, Error **errp); >> -void qdev_set_id(DeviceState *dev, char *id); >> +void qdev_set_id(DeviceState *dev, char *id, Error **errp); >>   #endif >> diff --git a/hw/xen/xen-legacy-backend.c b/hw/xen/xen-legacy-backend.c >> index dd8ae1452d..17aca85ddc 100644 >> --- a/hw/xen/xen-legacy-backend.c >> +++ b/hw/xen/xen-legacy-backend.c >> @@ -276,7 +276,8 @@ static struct XenLegacyDevice >> *xen_be_get_xendev(const char *type, int dom, >>       xendev = g_malloc0(ops->size); >>       object_initialize(&xendev->qdev, ops->size, TYPE_XENBACKEND); >>       OBJECT(xendev)->free = g_free; >> -    qdev_set_id(DEVICE(xendev), g_strdup_printf("xen-%s-%d", type, >> dev)); >> +    qdev_set_id(DEVICE(xendev), g_strdup_printf("xen-%s-%d", type, dev), >> +                &error_abort); >>       qdev_realize(DEVICE(xendev), xen_sysbus, &error_fatal); >>       object_unref(OBJECT(xendev)); >> diff --git a/softmmu/qdev-monitor.c b/softmmu/qdev-monitor.c >> index 1207e57a46..c2af906df0 100644 >> --- a/softmmu/qdev-monitor.c >> +++ b/softmmu/qdev-monitor.c >> @@ -593,26 +593,27 @@ static BusState *qbus_find(const char *path, >> Error **errp) >>   } >>   /* Takes ownership of @id, will be freed when deleting the device */ >> -void qdev_set_id(DeviceState *dev, char *id) >> +void qdev_set_id(DeviceState *dev, char *id, Error **errp) > > According to recommendations in error.h, worth adding also return value > (for example true=success false=failure), so [..] > >>   { >>       if (id) { >>           dev->id = id; >>       } > > Unrelated but.. What's the strange logic? > > Is it intended that with passed id=NULL we don't update dev->id variable > but try to do following logic with old dev->id? dev->id is expected to be NULL. The object is created just before calling this function so it is always the case. We could probably assert this. > >>       if (dev->id) { >> -        object_property_add_child(qdev_get_peripheral(), dev->id, >> -                                  OBJECT(dev)); >> +        object_property_try_add_child(qdev_get_peripheral(), dev->id, >> +                                      OBJECT(dev), errp); >>       } else { >>           static int anon_count; >>           gchar *name = g_strdup_printf("device[%d]", anon_count++); >> -        object_property_add_child(qdev_get_peripheral_anon(), name, >> -                                  OBJECT(dev)); >> +        object_property_try_add_child(qdev_get_peripheral_anon(), name, >> +                                      OBJECT(dev), errp); >>           g_free(name); >>       } >>   } >>   DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) >>   { >> +    ERRP_GUARD(); >>       DeviceClass *dc; >>       const char *driver, *path; >>       DeviceState *dev = NULL; >> @@ -691,7 +692,10 @@ DeviceState *qdev_device_add(QemuOpts *opts, >> Error **errp) >>           } >>       } >> -    qdev_set_id(dev, g_strdup(qemu_opts_id(opts))); >> +    qdev_set_id(dev, g_strdup(qemu_opts_id(opts)), errp); >> +    if (*errp) { >> +        goto err_del_dev; >> +    } > > [..] here we'll have > > if (!qdev_set_id(...)) { >   goto err_del_dev; > } > > and no need for ERRP_GUARD. > >>       /* set properties */ >>       if (qemu_opt_foreach(opts, set_property, dev, errp)) { >> > >