From nobody Mon Feb 9 07:22:38 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 1489699512635512.2745795958168; Thu, 16 Mar 2017 14:25:12 -0700 (PDT) Received: from localhost ([::1]:45841 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1coctT-0005I0-4F for importer@patchew.org; Thu, 16 Mar 2017 17:25:11 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40949) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cocsM-0005Bk-9D for qemu-devel@nongnu.org; Thu, 16 Mar 2017 17:24:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cocsK-0002an-U5 for qemu-devel@nongnu.org; Thu, 16 Mar 2017 17:24:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57530) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cocsG-0002YT-Ot; Thu, 16 Mar 2017 17:23:56 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B9DF37AE90; Thu, 16 Mar 2017 21:23:56 +0000 (UTC) Received: from scv.usersys.redhat.com (dhcp-17-221.bos.redhat.com [10.18.17.221]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0D1454FA21; Thu, 16 Mar 2017 21:23:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com B9DF37AE90 Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jsnow@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com B9DF37AE90 From: John Snow To: qemu-block@nongnu.org Date: Thu, 16 Mar 2017 17:23:50 -0400 Message-Id: <20170316212351.13797-3-jsnow@redhat.com> In-Reply-To: <20170316212351.13797-1-jsnow@redhat.com> References: <20170316212351.13797-1-jsnow@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 16 Mar 2017 21:23:56 +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 2/3] block-backend: add drained_begin / drained_end ops 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, jcody@redhat.com, John Snow , qemu-devel@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" Allow block backends to forward drain requests to their devices/users. The initial intended purpose for this patch is to allow BBs to forward requests along to BlockJobs, which will want to pause if their associated BB has entered a drained region. Signed-off-by: John Snow Reviewed-by: Jeff Cody --- block/block-backend.c | 24 ++++++++++++++++++++++-- include/sysemu/block-backend.h | 8 ++++++++ 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 5742c09..dec4a1c 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -65,6 +65,8 @@ struct BlockBackend { bool allow_write_beyond_eof; =20 NotifierList remove_bs_notifiers, insert_bs_notifiers; + + int quiesce_counter; }; =20 typedef struct BlockBackendAIOCB { @@ -699,12 +701,17 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDe= vOps *ops, void *opaque) { /* All drivers that use blk_set_dev_ops() are qdevified and we want to= keep - * it that way, so we can assume blk->dev is a DeviceState if blk->dev= _ops - * is set. */ + * it that way, so we can assume blk->dev, if present, is a DeviceStat= e if + * blk->dev_ops is set. Non-device users may use dev_ops without devic= e. */ assert(!blk->legacy_dev); =20 blk->dev_ops =3D ops; blk->dev_opaque =3D opaque; + + /* Are we currently quiesced? Should we enforce this right now? */ + if (blk->quiesce_counter && ops->drained_begin) { + ops->drained_begin(opaque); + } } =20 /* @@ -1870,6 +1877,12 @@ static void blk_root_drained_begin(BdrvChild *child) { BlockBackend *blk =3D child->opaque; =20 + if (++blk->quiesce_counter =3D=3D 1) { + if (blk->dev_ops && blk->dev_ops->drained_begin) { + blk->dev_ops->drained_begin(blk->dev_opaque); + } + } + /* Note that blk->root may not be accessible here yet if we are just * attaching to a BlockDriverState that is drained. Use child instead.= */ =20 @@ -1881,7 +1894,14 @@ static void blk_root_drained_begin(BdrvChild *child) static void blk_root_drained_end(BdrvChild *child) { BlockBackend *blk =3D child->opaque; + assert(blk->quiesce_counter); =20 assert(blk->public.io_limits_disabled); --blk->public.io_limits_disabled; + + if (--blk->quiesce_counter =3D=3D 0) { + if (blk->dev_ops && blk->dev_ops->drained_end) { + blk->dev_ops->drained_end(blk->dev_opaque); + } + } } diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 096c17f..7462228 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -58,6 +58,14 @@ typedef struct BlockDevOps { * Runs when the size changed (e.g. monitor command block_resize) */ void (*resize_cb)(void *opaque); + /* + * Runs when the backend receives a drain request. + */ + void (*drained_begin)(void *opaque); + /* + * Runs when the backend's last drain request ends. + */ + void (*drained_end)(void *opaque); } BlockDevOps; =20 /* This struct is embedded in (the private) BlockBackend struct and contai= ns --=20 2.9.3