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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 F29A8C4361A for ; Thu, 3 Dec 2020 15:29:21 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 73BF1206F6 for ; Thu, 3 Dec 2020 15:29:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73BF1206F6 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.43781.78643 (Exim 4.92) (envelope-from ) id 1kkqXa-0002V6-UN; Thu, 03 Dec 2020 15:29:06 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 43781.78643; Thu, 03 Dec 2020 15:29:06 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kkqXa-0002Uz-R0; Thu, 03 Dec 2020 15:29:06 +0000 Received: by outflank-mailman (input) for mailman id 43781; Thu, 03 Dec 2020 15:29:05 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kkqXZ-0002Uu-Fg for xen-devel@lists.xenproject.org; Thu, 03 Dec 2020 15:29:05 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id b10b02d5-7f06-4ec1-972c-e5f0a41e5e86; Thu, 03 Dec 2020 15:29:04 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D3C8CABCE; Thu, 3 Dec 2020 15:29:03 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: b10b02d5-7f06-4ec1-972c-e5f0a41e5e86 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1607009343; h=from:from:reply-to: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=+rozxxHWvd4WD/sJly2e0flB1+mp+wjGgFoB1B01LzY=; b=Om3iCYJcZiBku6VQBJx64lrNacSpxXs80HWGAy770fLH2L3X/SVPZGjK0CW3dkaXF3T8uM COEQkJGV/XWJVsEiA50E5aF17DIJIGvWPUeAjoZoirpadrcAYH0P++GF/NXHTatTM2lFGd uTt5vn50SCN+HVD9KHBrwrFPF5BrE/Q= Subject: Re: [PATCH v2 12/17] xen/hypfs: add new enter() and exit() per node callbacks To: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Cc: Andrew Cooper , George Dunlap , Ian Jackson , Julien Grall , Stefano Stabellini , Wei Liu , xen-devel@lists.xenproject.org References: <20201201082128.15239-1-jgross@suse.com> <20201201082128.15239-13-jgross@suse.com> <0c57dd86-36d9-c378-6bdb-50221a7812b8@suse.com> <2503547c-1b3c-2224-c4a9-c647d9d1a058@suse.com> From: Jan Beulich Message-ID: <6593ed01-23d0-70ac-faa3-556c69adec2b@suse.com> Date: Thu, 3 Dec 2020 16:29:03 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: <2503547c-1b3c-2224-c4a9-c647d9d1a058@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit On 03.12.2020 16:14, Jürgen Groß wrote: > On 03.12.20 15:59, Jan Beulich wrote: >> On 01.12.2020 09:21, Juergen Gross wrote: >>> @@ -100,11 +112,58 @@ static void hypfs_unlock(void) >>> } >>> } >>> >>> +const struct hypfs_entry *hypfs_node_enter(const struct hypfs_entry *entry) >>> +{ >>> + return entry; >>> +} >>> + >>> +void hypfs_node_exit(const struct hypfs_entry *entry) >>> +{ >>> +} >>> + >>> +static int node_enter(const struct hypfs_entry *entry) >>> +{ >>> + const struct hypfs_entry **last = &this_cpu(hypfs_last_node_entered); >>> + >>> + entry = entry->funcs->enter(entry); >>> + if ( IS_ERR(entry) ) >>> + return PTR_ERR(entry); >>> + >>> + ASSERT(!*last || *last == entry->parent); >>> + >>> + *last = entry; >>> + >>> + return 0; >>> +} >>> + >>> +static void node_exit(const struct hypfs_entry *entry) >>> +{ >>> + const struct hypfs_entry **last = &this_cpu(hypfs_last_node_entered); >>> + >>> + if ( !*last ) >>> + return; >> >> Under what conditions is this legitimate to happen? IOW shouldn't >> there be an ASSERT_UNREACHABLE() here? > > This is for the "/" node. I.e. would ASSERT(!entry->parent) be appropriate to add here, at the same time serving as documentation of what you've just said? Jan