From nobody Wed Oct 22 13:01:18 2025 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.zohomail.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; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1520433843815357.40675844978944; Wed, 7 Mar 2018 06:44:03 -0800 (PST) Received: from localhost ([::1]:33803 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etaIS-00043X-Ui for importer@patchew.org; Wed, 07 Mar 2018 09:44:00 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52989) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etaGo-0002iL-DR for qemu-devel@nongnu.org; Wed, 07 Mar 2018 09:42:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1etaGn-0004th-Hb for qemu-devel@nongnu.org; Wed, 07 Mar 2018 09:42:18 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50290 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1etaGl-0004pi-72; Wed, 07 Mar 2018 09:42:15 -0500 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 mx1.redhat.com (Postfix) with ESMTPS id 32F0141250CB; Wed, 7 Mar 2018 14:42:14 +0000 (UTC) Received: from localhost (ovpn-116-116.ams2.redhat.com [10.36.116.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id E9BE81102E23; Wed, 7 Mar 2018 14:42:08 +0000 (UTC) From: Stefan Hajnoczi To: Date: Wed, 7 Mar 2018 14:42:02 +0000 Message-Id: <20180307144205.20619-2-stefanha@redhat.com> In-Reply-To: <20180307144205.20619-1-stefanha@redhat.com> References: <20180307144205.20619-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Wed, 07 Mar 2018 14:42:14 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Wed, 07 Mar 2018 14:42:14 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'stefanha@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH v3 1/4] block: add aio_wait_bh_oneshot() 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, Peter Crosthwaite , "Michael S. Tsirkin" , Max Reitz , Stefan Hajnoczi , Paolo Bonzini , Richard Henderson 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" Sometimes it's necessary for the main loop thread to run a BH in an IOThread and wait for its completion. This primitive is useful during startup/shutdown to synchronize and avoid race conditions. Signed-off-by: Stefan Hajnoczi --- include/block/aio-wait.h | 13 +++++++++++++ util/aio-wait.c | 31 +++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h index a48c744fa8..f7a3972200 100644 --- a/include/block/aio-wait.h +++ b/include/block/aio-wait.h @@ -113,4 +113,17 @@ typedef struct { */ void aio_wait_kick(AioWait *wait); =20 +/** + * aio_wait_bh_oneshot: + * @ctx: the aio context + * @cb: the BH callback function + * @opaque: user data for the BH callback function + * + * Run a BH in @ctx and wait for it to complete. + * + * Must be called from the main loop thread with @ctx acquired exactly onc= e. + * Note that main loop event processing may occur. + */ +void aio_wait_bh_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque); + #endif /* QEMU_AIO_WAIT */ diff --git a/util/aio-wait.c b/util/aio-wait.c index a487cdb852..975afddf4c 100644 --- a/util/aio-wait.c +++ b/util/aio-wait.c @@ -38,3 +38,34 @@ void aio_wait_kick(AioWait *wait) aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL); } } + +typedef struct { + AioWait wait; + bool done; + QEMUBHFunc *cb; + void *opaque; +} AioWaitBHData; + +/* Context: BH in IOThread */ +static void aio_wait_bh(void *opaque) +{ + AioWaitBHData *data =3D opaque; + + data->cb(data->opaque); + + data->done =3D true; + aio_wait_kick(&data->wait); +} + +void aio_wait_bh_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque) +{ + AioWaitBHData data =3D { + .cb =3D cb, + .opaque =3D opaque, + }; + + assert(qemu_get_current_aio_context() =3D=3D qemu_get_aio_context()); + + aio_bh_schedule_oneshot(ctx, aio_wait_bh, &data); + AIO_WAIT_WHILE(&data.wait, ctx, !data.done); +} --=20 2.14.3