From patchwork Tue Oct 6 12:38:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 303604 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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=ham 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 76C94C4727D for ; Tue, 6 Oct 2020 12:50:12 +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 F3F00206F7 for ; Tue, 6 Oct 2020 12:50:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="g9MZaruD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3F00206F7 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]:42542 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kPmPz-0004Eo-4z for qemu-devel@archiver.kernel.org; Tue, 06 Oct 2020 08:50:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56164) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kPmG6-0001n6-KC for qemu-devel@nongnu.org; Tue, 06 Oct 2020 08:39:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:21048) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kPmG4-0007y9-SO for qemu-devel@nongnu.org; Tue, 06 Oct 2020 08:39:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601987996; 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=xLWcKme8gmgaxajj7sbx7gijC3D19suLECUMj7k2pac=; b=g9MZaruD0rBWQqh+JHS/YN6N6vXUvzcRCJQe8ZSMokJM4lhF15dtKyUNsbturAfoC2odCc Lb4aISj2xOJE5raFCXzUDVrB0vWEjXC6oVtUy2/gyWx1xcpsKJ+6PFxCgFFNbSwsTlPDyS A5Jqe+/NJpxCzU+OEGsEyyaiOuKJDqQ= 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-378-nUXZ8D1lNFe9y14Gtik38w-1; Tue, 06 Oct 2020 08:39:54 -0400 X-MC-Unique: nUXZ8D1lNFe9y14Gtik38w-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D60B018A0768; Tue, 6 Oct 2020 12:39:52 +0000 (UTC) Received: from localhost.localdomain (unknown [10.35.206.84]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9FE182C31E; Tue, 6 Oct 2020 12:39:45 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH v7 07/13] device_core: use drain_call_rcu in in qmp_device_add Date: Tue, 6 Oct 2020 15:38:58 +0300 Message-Id: <20201006123904.610658-8-mlevitsk@redhat.com> In-Reply-To: <20201006123904.610658-1-mlevitsk@redhat.com> References: <20201006123904.610658-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mlevitsk@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=63.128.21.124; envelope-from=mlevitsk@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/06 01:55:55 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.733, 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, 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: Fam Zheng , Laurent Vivier , Thomas Huth , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , qemu-block@nongnu.org, "Michael S. Tsirkin" , Stefan Hajnoczi , Jason Wang , Markus Armbruster , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Stefan Hajnoczi , Paolo Bonzini , Maxim Levitsky , John Snow , Stefan Berger Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Soon, a device removal might only happen on RCU callback execution. This is okay for device-del which provides a DEVICE_DELETED event, but not for the failure case of device-add. To avoid changing monitor semantics, just drain all pending RCU callbacks on error. Signed-off-by: Maxim Levitsky Suggested-by: Stefan Hajnoczi Reviewed-by: Stefan Hajnoczi Message-Id: <20200913160259.32145-4-mlevitsk@redhat.com> [Don't use it in qmp_device_del. - Paolo] Signed-off-by: Paolo Bonzini --- qdev-monitor.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/qdev-monitor.c b/qdev-monitor.c index e9b7228480..bcfb90a08f 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -803,6 +803,18 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp) return; } dev = qdev_device_add(opts, errp); + + /* + * Drain all pending RCU callbacks. This is done because + * some bus related operations can delay a device removal + * (in this case this can happen if device is added and then + * removed due to a configuration error) + * to a RCU callback, but user might expect that this interface + * will finish its job completely once qmp command returns result + * to the user + */ + drain_call_rcu(); + if (!dev) { qemu_opts_del(opts); return;