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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 B253BC4361B for ; Mon, 14 Dec 2020 17:08:15 +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 2C63F22510 for ; Mon, 14 Dec 2020 17:08:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C63F22510 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]:33400 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1korKY-0004RE-2c for qemu-devel@archiver.kernel.org; Mon, 14 Dec 2020 12:08:14 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53212) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1korJ2-0002ZB-CX for qemu-devel@nongnu.org; Mon, 14 Dec 2020 12:06:41 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:40003) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1korIz-0005bD-7q for qemu-devel@nongnu.org; Mon, 14 Dec 2020 12:06:40 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607965595; 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=/WpOYjMEI+uu6Ezu621PcgD7x1p7LtSJUlUJzLyqhGc=; b=XOVULEIEztPPiWzmO3yAaQsuuahBcplObOAWvg53dr7I0atWr2bQqXjfEI7rMMP6pJYe5i ovS1GQjb0j7wdL8VJHrKqsjGgGkK4nzKv3prx7Kd3Q7IbAO/FqQmybg4WmWQcDdzmF3AeR Uqz8Lm1uQiEWlbFGdxpMCgn181CEfG8= 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-244-D0CmhjvTOY6pEL_0tz-PPA-1; Mon, 14 Dec 2020 12:06:33 -0500 X-MC-Unique: D0CmhjvTOY6pEL_0tz-PPA-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 7C6511012EA3; Mon, 14 Dec 2020 17:06:19 +0000 (UTC) Received: from toolbox.redhat.com (ovpn-112-231.rdu2.redhat.com [10.10.112.231]) by smtp.corp.redhat.com (Postfix) with ESMTP id A9AEB5D6AB; Mon, 14 Dec 2020 17:05:37 +0000 (UTC) From: Sergio Lopez To: qemu-devel@nongnu.org Subject: [PATCH v2 2/4] block: Avoid processing BDS twice in bdrv_set_aio_context_ignore() Date: Mon, 14 Dec 2020 18:05:17 +0100 Message-Id: <20201214170519.223781-3-slp@redhat.com> In-Reply-To: <20201214170519.223781-1-slp@redhat.com> References: <20201214170519.223781-1-slp@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=slp@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=63.128.21.124; envelope-from=slp@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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: Kevin Wolf , Fam Zheng , Stefano Stabellini , Sergio Lopez , qemu-block@nongnu.org, Paul Durrant , "Michael S. Tsirkin" , Max Reitz , Stefan Hajnoczi , Paolo Bonzini , Anthony Perard , xen-devel@lists.xenproject.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" While processing the parents of a BDS, one of the parents may process the child that's doing the tail recursion, which leads to a BDS being processed twice. This is especially problematic for the aio_notifiers, as they might attempt to work on both the old and the new AIO contexts. To avoid this, add the BDS pointer to the ignore list, and check the child BDS pointer while iterating over the children. Signed-off-by: Sergio Lopez --- block.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index f1cedac362..bc8a66ab6e 100644 --- a/block.c +++ b/block.c @@ -6465,12 +6465,17 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, bdrv_drained_begin(bs); QLIST_FOREACH(child, &bs->children, next) { - if (g_slist_find(*ignore, child)) { + if (g_slist_find(*ignore, child) || g_slist_find(*ignore, child->bs)) { continue; } *ignore = g_slist_prepend(*ignore, child); bdrv_set_aio_context_ignore(child->bs, new_context, ignore); } + /* + * Add a reference to this BS to the ignore list, so its + * parents won't attempt to process it again. + */ + *ignore = g_slist_prepend(*ignore, bs); QLIST_FOREACH(child, &bs->parents, next_parent) { if (g_slist_find(*ignore, child)) { continue; -- 2.26.2