From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14DBAC43603 for ; Mon, 9 Dec 2019 16:07:56 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CB6ED20692 for ; Mon, 9 Dec 2019 16:07:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="I41x5Ajk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB6ED20692 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42032 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ieLZj-0003aB-0z for qemu-devel@archiver.kernel.org; Mon, 09 Dec 2019 11:07:55 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59173) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ieLZ5-0002xx-C3 for qemu-devel@nongnu.org; Mon, 09 Dec 2019 11:07:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ieLZ4-0000iG-A3 for qemu-devel@nongnu.org; Mon, 09 Dec 2019 11:07:15 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:59590 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ieLZ4-0000gb-5v for qemu-devel@nongnu.org; Mon, 09 Dec 2019 11:07:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575907633; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vP6VNKdJRcphu5z3jxbuaQmrRW1htck0r0LeJVfPd/E=; b=I41x5Ajkd6X45K7nMFcYQ5Aiyvyc1rhiL7bOPEnJTE0rAlfB/ycoDt9ZB+4DESXnhGj3CZ bRq3Eq6SBfWSqziUONyk+nBMB46ITtZrzsTKElIMydZ212l//15RoF4nbVYK+Hrzu/gyPn HKrP/2wi0b4TtkKs5H/mRF0jiCS73es= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-292-eoAheURvOV2BP3IedlUGjw-1; Mon, 09 Dec 2019 11:07:10 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0DE78800D53; Mon, 9 Dec 2019 16:07:09 +0000 (UTC) Received: from linux.fritz.box (ovpn-117-116.ams2.redhat.com [10.36.117.116]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E14F710016DA; Mon, 9 Dec 2019 16:07:05 +0000 (UTC) Date: Mon, 9 Dec 2019 17:07:04 +0100 From: Kevin Wolf To: Sergio Lopez Subject: Re: [PATCH v5 0/4] blockdev: avoid acquiring AioContext lock twice at do_drive_backup and do_blockdev_backup Message-ID: <20191209160704.GC6715@linux.fritz.box> References: <20191128104129.250206-1-slp@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191128104129.250206-1-slp@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: eoAheURvOV2BP3IedlUGjw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 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: Max Reitz , qemu-devel@nongnu.org, qemu-block@nongnu.org, Markus Armbruster Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 28.11.2019 um 11:41 hat Sergio Lopez geschrieben: > do_drive_backup() acquires the AioContext lock of the corresponding > BlockDriverState. This is not a problem when it's called from > qmp_drive_backup(), but drive_backup_prepare() also acquires the lock > before calling it. The same things happens with do_blockdev_backup() > and blockdev_backup_prepare(). >=20 > This patch series merges do_drive_backup() with drive_backup_prepare() > and do_blockdev_backup() with blockdev_backup_prepare(), and ensures > they're only getting called from a transaction context. This way, > there's a single code path for both transaction requests and qmp > commands, as suggested by Kevin Wolf. >=20 > We also take this opportunity to ensure we're honoring the context > acquisition semantics required by bdrv_try_set_aio_context, as > suggested by Max Reitz. I think there is a small problem with the error paths in patch 4, but for patches 1 to 3 you can add: Reviewed-by: Kevin Wolf