From nobody Wed Dec 17 21:59:23 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (209.51.188.17 [209.51.188.17]) by mx.zohomail.com with SMTPS id 1551108807673686.4831497604856; Mon, 25 Feb 2019 07:33:27 -0800 (PST) Received: from localhost ([127.0.0.1]:39170 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gyIFq-0001L8-H7 for importer@patchew.org; Mon, 25 Feb 2019 10:33:18 -0500 Received: from eggs.gnu.org ([209.51.188.92]:37347) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gyI4o-0000I3-9y for qemu-devel@nongnu.org; Mon, 25 Feb 2019 10:21:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gyI4h-0000ud-5j for qemu-devel@nongnu.org; Mon, 25 Feb 2019 10:21:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48298) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gyI4Z-0000l2-61; Mon, 25 Feb 2019 10:21:41 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F4078309703F; Mon, 25 Feb 2019 15:21:31 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-117-243.ams2.redhat.com [10.36.117.243]) by smtp.corp.redhat.com (Postfix) with ESMTP id E6CDA5C221; Mon, 25 Feb 2019 15:21:30 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Mon, 25 Feb 2019 16:19:58 +0100 Message-Id: <20190225152053.15976-17-kwolf@redhat.com> In-Reply-To: <20190225152053.15976-1-kwolf@redhat.com> References: <20190225152053.15976-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Mon, 25 Feb 2019 15:21:32 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 16/71] nbd: Increase bs->in_flight during AioContext switch 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: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" bdrv_drain() must not leave connection_co scheduled, so bs->in_flight needs to be increased while the coroutine is waiting to be scheduled in the new AioContext after nbd_client_attach_aio_context(). Signed-off-by: Kevin Wolf --- block/nbd-client.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/block/nbd-client.c b/block/nbd-client.c index 60f38f0320..bfbaf7ebe9 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -977,14 +977,30 @@ void nbd_client_detach_aio_context(BlockDriverState *= bs) qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc)); } =20 +static void nbd_client_attach_aio_context_bh(void *opaque) +{ + BlockDriverState *bs =3D opaque; + NBDClientSession *client =3D nbd_get_client_session(bs); + + /* The node is still drained, so we know the coroutine has yielded in + * nbd_read_eof(), the only place where bs->in_flight can reach 0, or = it is + * entered for the first time. Both places are safe for entering the + * coroutine.*/ + qemu_aio_coroutine_enter(bs->aio_context, client->connection_co); + bdrv_dec_in_flight(bs); +} + void nbd_client_attach_aio_context(BlockDriverState *bs, AioContext *new_context) { NBDClientSession *client =3D nbd_get_client_session(bs); qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc), new_context); =20 - /* FIXME Really need a bdrv_inc_in_flight() here */ - aio_co_schedule(new_context, client->connection_co); + bdrv_inc_in_flight(bs); + + /* Need to wait here for the BH to run because the BH must run while t= he + * node is still drained. */ + aio_wait_bh_oneshot(new_context, nbd_client_attach_aio_context_bh, bs); } =20 void nbd_client_close(BlockDriverState *bs) --=20 2.20.1