From nobody Sun Feb 8 08:43:18 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 1550686300192388.9776684724584; Wed, 20 Feb 2019 10:11:40 -0800 (PST) Received: from localhost ([127.0.0.1]:45101 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gwWLH-00078n-58 for importer@patchew.org; Wed, 20 Feb 2019 13:11:35 -0500 Received: from eggs.gnu.org ([209.51.188.92]:51680) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gwVzY-0005Dc-Hq for qemu-devel@nongnu.org; Wed, 20 Feb 2019 12:49:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gwVzX-00053g-6k for qemu-devel@nongnu.org; Wed, 20 Feb 2019 12:49:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45590) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gwVzU-0004yg-27; Wed, 20 Feb 2019 12:49:04 -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 2F1A31CFF58; Wed, 20 Feb 2019 17:49:03 +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 AD4413792; Wed, 20 Feb 2019 17:49:01 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Wed, 20 Feb 2019 18:48:32 +0100 Message-Id: <20190220174843.8847-3-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 17:49:03 +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 02/13] virtio-blk: Increase in_flight for request restart BH 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" virtio_blk_dma_restart_bh() submits new requests, so in order to make sure that these requests are not started inside a drained section of the attached BlockBackend, we need to make sure that draining the BlockBackend waits for the BH to be executed. This BH is still questionable because its scheduled in the main thread instead of the configured iothread. Leave a FIXME comment for this. But with this fix, enabling the data plane at least waits for these requests (in bdrv_set_aio_context()) instead of changing the AioContext under their feet and making them run in the wrong thread, causing crashes and failures (e.g. due to missing locking). Signed-off-by: Kevin Wolf --- hw/block/virtio-blk.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index cf7f47eaba..e11e6e45d0 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -675,6 +675,7 @@ static void virtio_blk_dma_restart_bh(void *opaque) if (mrb.num_reqs) { virtio_blk_submit_multireq(s->blk, &mrb); } + blk_dec_in_flight(s->conf.conf.blk); aio_context_release(blk_get_aio_context(s->conf.conf.blk)); } =20 @@ -688,8 +689,11 @@ static void virtio_blk_dma_restart_cb(void *opaque, in= t running, } =20 if (!s->bh) { + /* FIXME The data plane is not started yet, so these requests are + * processed in the main thread. */ s->bh =3D aio_bh_new(blk_get_aio_context(s->conf.conf.blk), virtio_blk_dma_restart_bh, s); + blk_inc_in_flight(s->conf.conf.blk); qemu_bh_schedule(s->bh); } } --=20 2.20.1