From nobody Mon Feb 9 08:34:10 2026 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 (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1550685491522618.9364656536517; Wed, 20 Feb 2019 09:58:11 -0800 (PST) Received: from localhost ([127.0.0.1]:44826 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gwW8G-0004Xe-Gt for importer@patchew.org; Wed, 20 Feb 2019 12:58:08 -0500 Received: from eggs.gnu.org ([209.51.188.92]:52022) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gwW07-0005fO-6U for qemu-devel@nongnu.org; Wed, 20 Feb 2019 12:49:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gwW04-0005WE-Jy for qemu-devel@nongnu.org; Wed, 20 Feb 2019 12:49:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46648) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gwW02-0005Ku-10; Wed, 20 Feb 2019 12:49:38 -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 DAF4E1CFF3D; Wed, 20 Feb 2019 17:49:28 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-117-82.ams2.redhat.com [10.36.117.82]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5E3F5171C1; Wed, 20 Feb 2019 17:49:27 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Wed, 20 Feb 2019 18:48:38 +0100 Message-Id: <20190220174843.8847-9-kwolf@redhat.com> In-Reply-To: <20190220174843.8847-1-kwolf@redhat.com> References: <20190220174843.8847-1-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 [10.5.110.38]); Wed, 20 Feb 2019 17:49:29 +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] [PATCH v2 08/13] 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, pbonzini@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com 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