From nobody Sat Feb 7 06:55:33 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1491548206739274.37250012481263; Thu, 6 Apr 2017 23:56:46 -0700 (PDT) Received: from localhost ([::1]:49259 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwNp7-0000zz-Hj for importer@patchew.org; Fri, 07 Apr 2017 02:56:45 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46103) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwNnV-00088P-KZ for qemu-devel@nongnu.org; Fri, 07 Apr 2017 02:55:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cwNnU-0004bv-Oy for qemu-devel@nongnu.org; Fri, 07 Apr 2017 02:55:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54460) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cwNnQ-0004We-8m; Fri, 07 Apr 2017 02:55:00 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2B29A61D22; Fri, 7 Apr 2017 06:54:59 +0000 (UTC) Received: from lemon.redhat.com (ovpn-8-27.pek2.redhat.com [10.72.8.27]) by smtp.corp.redhat.com (Postfix) with ESMTP id D790618983; Fri, 7 Apr 2017 06:54:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 2B29A61D22 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=famz@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 2B29A61D22 From: Fam Zheng To: qemu-devel@nongnu.org Date: Fri, 7 Apr 2017 14:54:12 +0800 Message-Id: <20170407065414.9143-5-famz@redhat.com> In-Reply-To: <20170407065414.9143-1-famz@redhat.com> References: <20170407065414.9143-1-famz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 07 Apr 2017 06:54:59 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 4/6] block: Quiesce old aio context during bdrv_set_aio_context X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Max Reitz , Ed Swierk , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The fact that the bs->aio_context is changing can confuse the dataplane iothread, because of the now fine granularity aio context lock. bdrv_drain should rather be a bdrv_drained_begin/end pair, but since bs->aio_context is changing, we can just use aio_disable_external and block_job_pause. Reported-by: Ed Swierk Reviewed-by: Eric Blake Signed-off-by: Fam Zheng --- block.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index b8a3011..512515a 100644 --- a/block.c +++ b/block.c @@ -4396,11 +4396,14 @@ void bdrv_attach_aio_context(BlockDriverState *bs, =20 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) { - AioContext *ctx; + AioContext *ctx =3D bdrv_get_aio_context(bs); =20 + aio_disable_external(ctx); + if (bs->job) { + block_job_pause(bs->job); + } bdrv_drain(bs); /* ensure there are no in-flight requests */ =20 - ctx =3D bdrv_get_aio_context(bs); while (aio_poll(ctx, false)) { /* wait for all bottom halves to execute */ } @@ -4413,6 +4416,10 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioC= ontext *new_context) aio_context_acquire(new_context); bdrv_attach_aio_context(bs, new_context); aio_context_release(new_context); + if (bs->job) { + block_job_resume(bs->job); + } + aio_enable_external(ctx); } =20 void bdrv_add_aio_context_notifier(BlockDriverState *bs, --=20 2.9.3