From patchwork Thu Jun 9 16:47:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 1641404 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.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=X4oYN+Zj; dkim-atps=neutral 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=) 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 bilbo.ozlabs.org (Postfix) with ESMTPS id 4LJt3f5ZGZz9s2R for ; Fri, 10 Jun 2022 04:31:57 +1000 (AEST) Received: from localhost ([::1]:45622 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nzMwk-0003k5-Be for incoming@patchwork.ozlabs.org; Thu, 09 Jun 2022 14:31:54 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48166) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nzLJb-0000gS-Pc for qemu-devel@nongnu.org; Thu, 09 Jun 2022 12:47:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:43393) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nzLJZ-0006VO-RI for qemu-devel@nongnu.org; Thu, 09 Jun 2022 12:47:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1654793240; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VlBXSLKPMbLopKgZce2Q2MK/CyVPgH2pSsygq+8Hmms=; b=X4oYN+ZjG0DXVjyBEOAZC2tePOcpkY+J5QrKbyV4kF+W727ODWZMMN6khd3AB0TwpivQHV apdguRAxbn/AmesEYbGOpLaWnb1sjpBtArkabxtQlXT3Od+KqO9G/QO0/xr7bcHX7hsaZ6 GYSblCCy3jhqFYVWqGpY7WItw4sCzdc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-502-82zejNysOkK5mXQc46yDgw-1; Thu, 09 Jun 2022 12:47:14 -0400 X-MC-Unique: 82zejNysOkK5mXQc46yDgw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9437F85A580; Thu, 9 Jun 2022 16:47:14 +0000 (UTC) Received: from localhost (unknown [10.39.193.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4708F1121314; Thu, 9 Jun 2022 16:47:14 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Hanna Reitz , qemu-stable@nongnu.org, Kevin Wolf , qemu-block@nongnu.org, Stefan Hajnoczi , Nikolay Tenev , Stefano Garzarella Subject: [PATCH 1/2] linux-aio: fix unbalanced plugged counter in laio_io_unplug() Date: Thu, 9 Jun 2022 17:47:11 +0100 Message-Id: <20220609164712.1539045-2-stefanha@redhat.com> In-Reply-To: <20220609164712.1539045-1-stefanha@redhat.com> References: <20220609164712.1539045-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Every laio_io_plug() call has a matching laio_io_unplug() call. There is a plugged counter that tracks the number of levels of plugging and allows for nesting. The plugged counter must reflect the balance between laio_io_plug() and laio_io_unplug() calls accurately. Otherwise I/O stalls occur since io_submit(2) calls are skipped while plugged. Reported-by: Nikolay Tenev Cc: Stefano Garzarella Signed-off-by: Stefan Hajnoczi Reviewed-by: Stefano Garzarella --- block/linux-aio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/linux-aio.c b/block/linux-aio.c index 4c423fcccf..6078da7e42 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -363,8 +363,10 @@ void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s, uint64_t dev_max_batch) { assert(s->io_q.plugged); + s->io_q.plugged--; + if (s->io_q.in_queue >= laio_max_batch(s, dev_max_batch) || - (--s->io_q.plugged == 0 && + (!s->io_q.plugged && !s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending))) { ioq_submit(s); }