From patchwork Wed Jun 19 15:25:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 11004511 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 43F40112C for ; Wed, 19 Jun 2019 15:31:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 34B7D28451 for ; Wed, 19 Jun 2019 15:31:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 28E8928A1A; Wed, 19 Jun 2019 15:31:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B618B28A52 for ; Wed, 19 Jun 2019 15:31:12 +0000 (UTC) Received: from localhost ([::1]:39476 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdcYJ-0000yL-Sn for patchwork-qemu-devel@patchwork.kernel.org; Wed, 19 Jun 2019 11:31:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42475) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdcTw-0003Hk-QR for qemu-devel@nongnu.org; Wed, 19 Jun 2019 11:26:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hdcTv-0002CQ-KZ for qemu-devel@nongnu.org; Wed, 19 Jun 2019 11:26:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39970) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hdcTs-00026V-SY; Wed, 19 Jun 2019 11:26:37 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A9030981D3; Wed, 19 Jun 2019 15:26:25 +0000 (UTC) Received: from localhost (ovpn-116-121.ams2.redhat.com [10.36.116.121]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 47E7A5C2E8; Wed, 19 Jun 2019 15:26:25 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 19 Jun 2019 17:25:59 +0200 Message-Id: <20190619152603.5937-6-mreitz@redhat.com> In-Reply-To: <20190619152603.5937-1-mreitz@redhat.com> References: <20190619152603.5937-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 19 Jun 2019 15:26:25 +0000 (UTC) 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 5/9] block: Add @poll to bdrv_parent_drained_end_single() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-devel@nongnu.org, Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP This function has two callers; one wants it to poll, the other does not. To implement this parameter, we also need a new BdrvChildRole method, namely .drained_end_unquiesce(). This function differs from .drained_end() in that it should poll and is thus allowed to modify the block graph. Note that currently every BDS child's .drained_end() implementation is simply broken in exactly that regard; the current implementation is actually fit for .drained_end_unquiesce(). However, at this point we cannot implement .drained_end() correctly, so a later patch in this series will address that issue. Signed-off-by: Max Reitz --- include/block/block.h | 5 ++++- include/block/block_int.h | 14 ++++++++++++++ block.c | 2 +- block/io.c | 10 +++++++--- 4 files changed, 26 insertions(+), 5 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index 3c084e8222..d98237f0f1 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -620,8 +620,11 @@ void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll); * bdrv_parent_drained_end_single: * * End a quiesced section for the parent of @c. + * + * If @poll is true, poll until the parent is unquiesced. This may + * lead to changes in the block graph. */ -void bdrv_parent_drained_end_single(BdrvChild *c); +void bdrv_parent_drained_end_single(BdrvChild *c, bool poll); /** * bdrv_parent_drained_end: diff --git a/include/block/block_int.h b/include/block/block_int.h index 7f62907932..fce9a9e7ee 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -670,6 +670,20 @@ struct BdrvChildRole { void (*drained_begin)(BdrvChild *child); void (*drained_end)(BdrvChild *child); + /* + * Parents that require polling to actually become unquiesced + * should implement this function in addition to .drained_end(). + * In it, the parent should end the drain and aio_poll() until it + * is no longer quiesced. + * + * Thus, in contrast to .drained_end(), this function is allowed + * to change the graph. + * + * (This pointer may be NULL, in which case .drained_end() is + * called instead.) + */ + void (*drained_end_unquiesce)(BdrvChild *child); + /* * Returns whether the parent has pending requests for the child. This * callback is polled after .drained_begin() has been called until all diff --git a/block.c b/block.c index f7d7d8ccef..31b85df0f0 100644 --- a/block.c +++ b/block.c @@ -2252,7 +2252,7 @@ static void bdrv_replace_child_noperm(BdrvChild *child, child->role->detach(child); } while (child->parent_quiesce_counter) { - bdrv_parent_drained_end_single(child); + bdrv_parent_drained_end_single(child, true); } QLIST_REMOVE(child, next_parent); } else { diff --git a/block/io.c b/block/io.c index 426ad5b4a1..5f30baa8e5 100644 --- a/block/io.c +++ b/block/io.c @@ -55,12 +55,16 @@ void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore, } } -void bdrv_parent_drained_end_single(BdrvChild *c) +void bdrv_parent_drained_end_single(BdrvChild *c, bool poll) { assert(c->parent_quiesce_counter > 0); c->parent_quiesce_counter--; if (c->role->drained_end) { - c->role->drained_end(c); + if (poll && c->role->drained_end_unquiesce) { + c->role->drained_end_unquiesce(c); + } else { + c->role->drained_end(c); + } } } @@ -73,7 +77,7 @@ void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore, if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) { continue; } - bdrv_parent_drained_end_single(c); + bdrv_parent_drained_end_single(c, false); } }