From nobody Mon Feb 9 09:33:42 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 1495190403663851.4542893685551; Fri, 19 May 2017 03:40:03 -0700 (PDT) Received: from localhost ([::1]:57710 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBfKD-0006fH-Um for importer@patchew.org; Fri, 19 May 2017 06:40:02 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33906) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBfDW-000190-7E for qemu-devel@nongnu.org; Fri, 19 May 2017 06:33:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dBfDS-00081T-HV for qemu-devel@nongnu.org; Fri, 19 May 2017 06:33:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43210) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dBfDQ-00080Q-Gd; Fri, 19 May 2017 06:33:00 -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 7EEC9C056782; Fri, 19 May 2017 10:32:59 +0000 (UTC) Received: from localhost (ovpn-117-50.ams2.redhat.com [10.36.117.50]) by smtp.corp.redhat.com (Postfix) with ESMTP id C2B51189EF; Fri, 19 May 2017 10:32:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 7EEC9C056782 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=stefanha@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 7EEC9C056782 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Date: Fri, 19 May 2017 11:32:45 +0100 Message-Id: <20170519103247.4405-3-stefanha@redhat.com> In-Reply-To: <20170519103247.4405-1-stefanha@redhat.com> References: <20170519103247.4405-1-stefanha@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 [10.5.110.32]); Fri, 19 May 2017 10:32:59 +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 2/4] block: use BDRV_POLL_WHILE() in bdrv_rw_vmstate() 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 , Paolo Bonzini , Fam Zheng , Stefan Hajnoczi , qemu-block@nongnu.org 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" Calling aio_poll() directly may have been fine previously, but this is the future, man! The difference between an aio_poll() loop and BDRV_POLL_WHILE() is that BDRV_POLL_WHILE() releases the AioContext around aio_poll(). This allows the IOThread to run fd handlers or BHs to complete the request. Failure to release the AioContext causes deadlocks. Using BDRV_POLL_WHILE() partially fixes a 'savevm' hang with -object iothread. Signed-off-by: Stefan Hajnoczi Reviewed-by: Eric Blake Reviewed-by: Paolo Bonzini --- block/io.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/block/io.c b/block/io.c index cc56e90..f0041cd 100644 --- a/block/io.c +++ b/block/io.c @@ -2031,9 +2031,7 @@ bdrv_rw_vmstate(BlockDriverState *bs, QEMUIOVector *q= iov, int64_t pos, Coroutine *co =3D qemu_coroutine_create(bdrv_co_rw_vmstate_entry, = &data); =20 bdrv_coroutine_enter(bs, co); - while (data.ret =3D=3D -EINPROGRESS) { - aio_poll(bdrv_get_aio_context(bs), true); - } + BDRV_POLL_WHILE(bs, data.ret =3D=3D -EINPROGRESS); return data.ret; } } --=20 2.9.3