From patchwork Tue Feb 2 16:28:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 1434828 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=EhxEsFa9; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 4DVW172cKBz9sVF for ; Wed, 3 Feb 2021 03:46:35 +1100 (AEDT) Received: from localhost ([::1]:40398 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l6yoz-00027G-Bx for incoming@patchwork.ozlabs.org; Tue, 02 Feb 2021 11:46:33 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:52416) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l6yY8-00057Q-Jy for qemu-devel@nongnu.org; Tue, 02 Feb 2021 11:29:09 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:47064) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l6yY1-00009f-TC for qemu-devel@nongnu.org; Tue, 02 Feb 2021 11:29:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612283341; 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=EhxEsFa95x0GZYjPjd+6ZOyO1SwbQPjVaGsaufpn0uoWRFUZ2NSOxfXzxo0vTAtZljSZXo BUXjmDEr4TBQWHlf7o9Sk3S1eLIr/wxhyclsiMiw15DcGtN5PeUmT/bKgKQGsb8nhE9HsX 7ZadmNbrzxQyirEPvfH56vUMWMUjKxk= 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-242-7XRkl_aKM4mOVrlfLzYVIw-1; Tue, 02 Feb 2021 11:28:57 -0500 X-MC-Unique: 7XRkl_aKM4mOVrlfLzYVIw-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 0839F80B727; Tue, 2 Feb 2021 16:28:56 +0000 (UTC) Received: from merkur.fritz.box (ovpn-112-19.ams2.redhat.com [10.36.112.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6027C5D749; Tue, 2 Feb 2021 16:28:53 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL v2 02/10] block: Avoid processing BDS twice in bdrv_set_aio_context_ignore() Date: Tue, 2 Feb 2021 17:28:26 +0100 Message-Id: <20210202162834.269789-3-kwolf@redhat.com> In-Reply-To: <20210202162834.269789-1-kwolf@redhat.com> References: <20210202162834.269789-1-kwolf@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=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=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+incoming=patchwork.ozlabs.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);