From patchwork Sun Sep 13 16:02:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 273879 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 9B8A4C43461 for ; Sun, 13 Sep 2020 16:05:59 +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 2BE2C206B8 for ; Sun, 13 Sep 2020 16:05:56 +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="DOAYB8By" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2BE2C206B8 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]:48038 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHUVn-0007Hz-9C for qemu-devel@archiver.kernel.org; Sun, 13 Sep 2020 12:05:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54252) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHUTM-0002Nj-Lb for qemu-devel@nongnu.org; Sun, 13 Sep 2020 12:03:24 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:25158 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 1kHUTK-0001PE-QT for qemu-devel@nongnu.org; Sun, 13 Sep 2020 12:03:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600013001; 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=T9AFma23LBkYxDC875+y6zL/RyokUGeWCTcMzCRTxYM=; b=DOAYB8By2NVNOAi7RM0IeAt5Uuj6inDs718IDYb1cGZW28NOgZrv/JeiU+1BCIYKeDX2KJ 0lmjPsrxtpQ4bhStfgazXQa+TUSzD2+NjMLnx+YAEGsQOO8N5Ebkjyz2DvHnBa11ytxbXX WMKl7uXU0CbOaVPZeN2v9aIwLi1GjlY= 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-169-jb55kTeAOjixfduLYOn5sQ-1; Sun, 13 Sep 2020 12:03:20 -0400 X-MC-Unique: jb55kTeAOjixfduLYOn5sQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EB70B801AAD; Sun, 13 Sep 2020 16:03:18 +0000 (UTC) Received: from localhost.localdomain (unknown [10.35.206.72]) by smtp.corp.redhat.com (Postfix) with ESMTP id 75FC619C4F; Sun, 13 Sep 2020 16:03:16 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Subject: [PATCH v5 3/9] device_core: use drain_call_rcu in in hmp_device_del/qmp_device_add Date: Sun, 13 Sep 2020 19:02:53 +0300 Message-Id: <20200913160259.32145-4-mlevitsk@redhat.com> In-Reply-To: <20200913160259.32145-1-mlevitsk@redhat.com> References: <20200913160259.32145-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mlevitsk@redhat.com X-Mimecast-Spam-Score: 0.0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=mlevitsk@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/13 11:31:53 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -37 X-Spam_score: -3.8 X-Spam_bar: --- X-Spam_report: (-3.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.695, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: Fam Zheng , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , "Michael S. Tsirkin" , Stefan Hajnoczi , Maxim Levitsky , Stefan Hajnoczi , Paolo Bonzini 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, but to avoid chanding HMP semantics, just drain all pending RCU callbacks Signed-off-by: Maxim Levitsky Suggested-by: Stefan Hajnoczi Reviewed-by: Stefan Hajnoczi --- qdev-monitor.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/qdev-monitor.c b/qdev-monitor.c index e9b7228480..c66ba13780 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; @@ -894,6 +906,16 @@ void qmp_device_del(const char *id, Error **errp) } qdev_unplug(dev, errp); + + /* + * Drain all pending RCU callbacks. This is done because + * some bus related operations can delay a device removal + * 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(); } }