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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 A460FC433DB for ; Mon, 1 Feb 2021 19:09:36 +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 1626964E8D for ; Mon, 1 Feb 2021 19:09:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1626964E8D 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]:49988 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l6eZr-0005Vs-1A for qemu-devel@archiver.kernel.org; Mon, 01 Feb 2021 14:09:35 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41872) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l6eXz-0003ks-A9 for qemu-devel@nongnu.org; Mon, 01 Feb 2021 14:07:39 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:50040) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l6eXx-0000Oz-Nd for qemu-devel@nongnu.org; Mon, 01 Feb 2021 14:07:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612206457; 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=/UPzXrJ27AqJD479c69kO56oBloOrR2rW0hBBE0pdeM=; b=cTToOm+SSMojEm544KtCw/gEGP9ar6Oxs+XhrzB7/FONJW+7rNc0hVejmeuSe4bkQ4KckU kdZSMNV7192oXjU5qa19yR7RIXH5TpCTGcr/zoMxk4JFM3swAhGLro/kt8TLlVms/hOC7R 4ZRwSm71fet09BhOySYMsIqxoQpnIek= 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-558-aFBTATnuPOKPHDOpzAKQKg-1; Mon, 01 Feb 2021 14:07:33 -0500 X-MC-Unique: aFBTATnuPOKPHDOpzAKQKg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EFDB081620; Mon, 1 Feb 2021 19:07:31 +0000 (UTC) Received: from merkur.fritz.box (ovpn-112-72.ams2.redhat.com [10.36.112.72]) by smtp.corp.redhat.com (Postfix) with ESMTP id 03F8560C05; Mon, 1 Feb 2021 19:07:30 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL 2/6] block: Avoid processing BDS twice in bdrv_set_aio_context_ignore() Date: Mon, 1 Feb 2021 20:07:16 +0100 Message-Id: <20210201190720.245732-3-kwolf@redhat.com> In-Reply-To: <20210201190720.245732-1-kwolf@redhat.com> References: <20210201190720.245732-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@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=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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=-0.351, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=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: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Sergio Lopez Some graphs may contain an indirect reference to the first BDS in the chain that can be reached while walking it bottom->up from one its children. Doubling-processing of a BDS 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 problem, add every child and parent to the ignore list before actually processing them. Suggested-by: Kevin Wolf Signed-off-by: Sergio Lopez Message-Id: <20210201125032.44713-2-slp@redhat.com> Signed-off-by: Kevin Wolf --- block.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) diff --git a/block.c b/block.c index 91a66d4f3e..5c428e1595 100644 --- a/block.c +++ b/block.c @@ -6439,7 +6439,10 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, AioContext *new_context, GSList **ignore) { AioContext *old_context = bdrv_get_aio_context(bs); - BdrvChild *child; + GSList *children_to_process = NULL; + GSList *parents_to_process = NULL; + GSList *entry; + BdrvChild *child, *parent; g_assert(qemu_get_current_aio_context() == qemu_get_aio_context()); @@ -6454,16 +6457,33 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, continue; } *ignore = g_slist_prepend(*ignore, child); - bdrv_set_aio_context_ignore(child->bs, new_context, ignore); + children_to_process = g_slist_prepend(children_to_process, child); } - QLIST_FOREACH(child, &bs->parents, next_parent) { - if (g_slist_find(*ignore, child)) { + + QLIST_FOREACH(parent, &bs->parents, next_parent) { + if (g_slist_find(*ignore, parent)) { continue; } - assert(child->klass->set_aio_ctx); - *ignore = g_slist_prepend(*ignore, child); - child->klass->set_aio_ctx(child, new_context, ignore); + *ignore = g_slist_prepend(*ignore, parent); + parents_to_process = g_slist_prepend(parents_to_process, parent); + } + + for (entry = children_to_process; + entry != NULL; + entry = g_slist_next(entry)) { + child = entry->data; + bdrv_set_aio_context_ignore(child->bs, new_context, ignore); + } + g_slist_free(children_to_process); + + for (entry = parents_to_process; + entry != NULL; + entry = g_slist_next(entry)) { + parent = entry->data; + assert(parent->klass->set_aio_ctx); + parent->klass->set_aio_ctx(parent, new_context, ignore); } + g_slist_free(parents_to_process); bdrv_detach_aio_context(bs); -- 2.29.2