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 90BB6C433E0 for ; Thu, 14 May 2020 07:35:28 +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 61484206D8 for ; Thu, 14 May 2020 07:35:28 +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="HfAU4cP1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61484206D8 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]:50146 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZ8Ot-0004Xk-Ev for qemu-devel@archiver.kernel.org; Thu, 14 May 2020 03:35:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46344) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZ8OC-0003fy-N2 for qemu-devel@nongnu.org; Thu, 14 May 2020 03:34:44 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:27884 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jZ8OB-000608-Uc for qemu-devel@nongnu.org; Thu, 14 May 2020 03:34:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589441682; 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=hcOO00NHa30yx3yEfCTop2Shjn1UwfhmpAPx6kXzsLI=; b=HfAU4cP1r2WfNFgTsTRisXe3WmzV+rjq+p66aTcfJiqSOdG5KMJj/yy9sqqGTCnWjBSbWQ Ct96Mjsrr1hybMsu3ZD+dzxx0eL6rHPhI91eBEY5TyKI3nZCk7YIKiBzklNichK6rDGdE8 ZwswhREqr1qHdd6BHwUaKKh/1Wi+2c0= 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-495-IBharCGUM8ihmoLoopHrTw-1; Thu, 14 May 2020 03:34:40 -0400 X-MC-Unique: IBharCGUM8ihmoLoopHrTw-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 38AAC461; Thu, 14 May 2020 07:34:39 +0000 (UTC) Received: from [10.72.12.133] (ovpn-12-133.pek2.redhat.com [10.72.12.133]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6224360BF1; Thu, 14 May 2020 07:34:26 +0000 (UTC) Subject: Re: [PATCH v2 5/5] vhost: add device started check in migration set log To: Dima Stepanov References: <20200511092541.GA27558@dimastep-nix> <20200512093521.GA5363@dimastep-nix> <20200512235934-mutt-send-email-mst@kernel.org> <20200513094703.GA15906@dimastep-nix> From: Jason Wang Message-ID: <722839b2-9412-b768-3ce6-d1b697d6d5dd@redhat.com> Date: Thu, 14 May 2020 15:34:24 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200513094703.GA15906@dimastep-nix> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/13 22:25:46 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: fam@euphon.net, kwolf@redhat.com, yc-core@yandex-team.ru, qemu-block@nongnu.org, "Michael S. Tsirkin" , qemu-devel@nongnu.org, dgilbert@redhat.com, arei.gonglei@huawei.com, fengli@smartx.com, stefanha@redhat.com, marcandre.lureau@redhat.com, pbonzini@redhat.com, raphael.norwitz@nutanix.com, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/5/13 下午5:47, Dima Stepanov wrote: >>> case CHR_EVENT_CLOSED: >>> /* a close event may happen during a read/write, but vhost >>> * code assumes the vhost_dev remains setup, so delay the >>> * stop & clear to idle. >>> * FIXME: better handle failure in vhost code, remove bh >>> */ >>> if (s->watch) { >>> AioContext *ctx = qemu_get_current_aio_context(); >>> >>> g_source_remove(s->watch); >>> s->watch = 0; >>> qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL, >>> NULL, NULL, false); >>> >>> aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque); >>> } >>> break; >>> >>> I think it's time we dropped the FIXME and moved the handling to common >>> code. Jason? Marc-André? >> I agree. Just to confirm, do you prefer bh or doing changes like what is >> done in this series? It looks to me bh can have more easier codes. > Could it be a good idea just to make disconnect in the char device but > postphone clean up in the vhost-user-blk (or any other vhost-user > device) itself? So we are moving the postphone logic and decision from > the char device to vhost-user device. One of the idea i have is as > follows: > - Put ourself in the INITIALIZATION state > - Start these vhost-user "handshake" commands > - If we got a disconnect error, perform disconnect, but don't clean up > device (it will be clean up on the roll back). I can be done by > checking the state in vhost_user_..._disconnect routine or smth like it Any issue you saw just using the aio bh as Michael posted above. Then we don't need to deal with the silent vhost_dev_stop() and we will have codes that is much more easier to understand. Thank > - vhost-user command returns error back to the _start() routine > - Rollback in one place in the start() routine, by calling this > postphoned clean up for the disconnect >