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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 63DF6C433DB for ; Tue, 19 Jan 2021 14:43:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 262C020DD4 for ; Tue, 19 Jan 2021 14:43:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388842AbhASOkX (ORCPT ); Tue, 19 Jan 2021 09:40:23 -0500 Received: from esa4.hc3370-68.iphmx.com ([216.71.155.144]:20132 "EHLO esa4.hc3370-68.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390432AbhASKWz (ORCPT ); Tue, 19 Jan 2021 05:22:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1611051774; h=date:from:to:cc:subject:message-id:references: content-transfer-encoding:in-reply-to:mime-version; bh=UFn2COXuBHxblLRGoZBsxxh6zIy1E1Z4KkjjEeYPCRs=; b=cCImYnxNrb/au5p9qn4nTJkDtxXUdFkO2fta++FAThR59T+rDN9p8AzI gD9iF3b5z/u9vcBFb5In/KQZDOm40WQt3ZBqqWyt9qzUy566uim05fiAw Mjt9vJk9JJW2pXk4/KX0qDWsZKewFKxU90QPBD3W1r4U0q/Jxt699n4nr 4=; Authentication-Results: esa4.hc3370-68.iphmx.com; dkim=pass (signature verified) header.i=@citrix.onmicrosoft.com IronPort-SDR: UF7WhgJgjWLU9lGOyA3tr2U4FskkHg1LRT2LTcBI2t8idR4pP4NOOu74oP8M8ZqwGlGYxFXXLK 9LpwqsILAKrivRJyQdM+z+E2aYd4JSd5LQtUZ7GT6N5kU6zQ0++iUGTbGhHq9lXphEW+6CY2/e akixllOzaaE2GYV2iDNO3uXvx5Mn8rr+TzqpXlbp9ZxSXYhNuedGixSLaZGSD5JYTx3sigQD0H O+5HRwH5jq6YhDhI15RWTDK50G9quYjnbzwFBzpcIAJZQax9/Tgyl+x1czgk8aaYI3tlcaHRBy ffQ= X-SBRS: 5.2 X-MesageID: 36650108 X-Ironport-Server: esa4.hc3370-68.iphmx.com X-Remote-IP: 162.221.156.83 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.79,358,1602561600"; d="scan'208";a="36650108" ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Rx2qv89ObsXUVHxHuCpF06QAbyTzkNzxZcZGD5Lnw854gm+PaVHkuHKntc3aQR0J2fGzpsYB8+/SkfliPKh1s5Mvv9KRv9bh7VtPXf0T1og/OljE3hCakCulUkjVuv8AkhnaUeywOWJv7k1Vc0D3mQR8/2hYsvaVTc7HHhFTqMJYLyXfcD0hzu9gnlWTencZcskzJWPgLuPNGUftbxE+hry8irqAZOeZW9PPK1O2hOeUU0HAGsOLUnp0tZwBzFSWWw55mkf3fN1I9B9Ygz/DkgE9T450WyfGmCusVLRBo1pZkI+4oSFlf/1R5DcmnD161B0FOCvQO75a/G7qTEnmOw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=HFDSjVH+Td1ailRqBHdNwccecEOujYQNjO/T5gnFcuA=; b=FBFYmTkcqC76WPyz1HbSGlGTICeONN8o5QXoH/eckczuCZK0pEt5FXvRZS4aaKrA3H1TUlycNWf069diPf6gbxxSYr+COtrhUoibF3r1B/39LXDboaRE+pAlBJhln6e+1kFAWzt4fv03l+pGenuMT9YoOovpvcNxZBZeH6MxmDsVwjHtA2zX841BROMhxSrXNf4V+1w4UV3nS9KraXRZkKQ60uu8VxyH7dmJrL0em8z+EiG0+sJJvGTB7CuNWzu+3FWejIiaZTa4Iz1mkszJsPRQO/NrKb+sKGG8Ra2vbOKmYDO6GTr8jSPKyHzQrINQUfyb6/0K4guIFko34Wm5DA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.onmicrosoft.com; s=selector2-citrix-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=HFDSjVH+Td1ailRqBHdNwccecEOujYQNjO/T5gnFcuA=; b=LcqvNk7YtJBlO6YDEx3oCPrOSUIIxVqUxXmjfdj5C6gd93yMVusUzIrXZAivzn5S96KrOi1LNdMPvmt729TMl/hozlhK07Z7zjfI9efBAAgmyEAMOPURd0Srbj4N9+71DoGhWUFP8l3ByCkmUXDpH/CYwk91hWKv/0z3C/5+syE= Date: Tue, 19 Jan 2021 11:21:39 +0100 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: =?utf-8?B?SsO8cmdlbiBHcm/Dnw==?= CC: , Arthur Borsboom , Boris Ostrovsky , Stefano Stabellini , Konrad Rzeszutek Wilk , Jens Axboe , , Subject: Re: [PATCH] xen-blkfront: don't make discard-alignment mandatory Message-ID: <20210119102139.4zzfb2heytfsetmg@Air-de-Roger> References: <20210118151528.81668-1-roger.pau@citrix.com> <7cef385d-efe3-2661-bee2-9d21f159a5fb@suse.com> <20210119100651.afyccratx6ha52kc@Air-de-Roger> <20969962-331d-50d9-dc65-772b564ab1c6@suse.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20969962-331d-50d9-dc65-772b564ab1c6@suse.com> X-ClientProxiedBy: AM5PR0502CA0005.eurprd05.prod.outlook.com (2603:10a6:203:91::15) To DS7PR03MB5608.namprd03.prod.outlook.com (2603:10b6:5:2c9::18) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: fe5124b2-3780-43b4-6d17-08d8bc64053d X-MS-TrafficTypeDiagnostic: DM5PR03MB2556: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:1051; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: C4mAq4zmzSLZ9qjAv3eZdlGG2pPLq5I4rosWhzIzjbXJ3sB28IsHvJsy7BHOfrCtVcO32WW52nJGbpk+xAEU66Uf5HGWpD1F3KTm5fGQ7Ae2bC78A4IoO5ZxY6niSjCP/Y8hCua3PHN5rRkHdTF3unV7P2eSY/6t+ZbF37PfQuT1K6OWmBjbbAYgWCwAC3ci2qDYV77czwH9oe/NeTMEaDM3DCmFrgmuq1VKk5JHRgJH0zNRwPkTAH7gK5sAN8wrcQ0d1lYE7um/P58u5sfqKNB7XgG/FWQUr0gUzEHsemQroQkl2IOHIP0WoJKCjCoCnnltVpS5YFAfUoEPPYBsonbxeWb/QLAMJwk+X8k9fTJGmG9tLTM7lxbEWfQqIOiMR6vjFsg7xjpV/pS1IFHAfQ== X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS7PR03MB5608.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(7916004)(346002)(376002)(136003)(366004)(39860400002)(396003)(9686003)(5660300002)(1076003)(66574015)(66946007)(2906002)(6916009)(86362001)(6486002)(316002)(54906003)(83380400001)(478600001)(85182001)(53546011)(6496006)(26005)(8936002)(33716001)(66556008)(16526019)(956004)(186003)(8676002)(6666004)(4326008)(66476007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?NTVla2NiQWxnYmZiY0VNbWhQYXpUR3h6SHZnN0J2QjhPTGs1dVNqNkxoY0x4?= =?utf-8?B?ckhaTTIzdUxIbWtPVUVlMktGcW0zS0JYWVJubFhZb2MyeUxIVHprRWpNaW1U?= =?utf-8?B?TnFaL1NkbjVKdUp4T0hvZ01VWnVSanJOUEFZV2JSd1VIYzN3OVpRSkw1Nzg3?= =?utf-8?B?QmFkdFNBOVIwVU1pVnZjcjZnVVBHd09TNzB3Rll0MHM2U1RtdC9Ya01EYTFV?= =?utf-8?B?U0V0SThLQ3lPSE5mbzRnWjhrM1kzd2NEbHBNeDVnM0Y0WFhvTGV0U0JYNEZl?= =?utf-8?B?M3c5WVM0dldJcnpuSnVKWDdMWXl3WVNXR0U0Sm5CWHQvY0RINVVvRHlyQ2FV?= =?utf-8?B?SzVOYmxjYjBZb2pKczF0VFhmNTZjSkdWc2RCZ2M4aUFlU2swL0RUcUttdVhV?= =?utf-8?B?NnBub2RZOS9MK2FmbnR6aTBHbUE3L28rY3VnY1RZdWIraWw0Z2NLUGdsZ1px?= =?utf-8?B?S2kwWk1Kb1FocTMvbzVQdFBmYjRKZ1NqQUYwbi9SQndnK1kwNzZsWHh0MWo1?= =?utf-8?B?ZVVLemVKc3pONlVBMzJrSndMY0poQnNUaHRNSXgzbFRhVkd3WWlxTUpOclpC?= =?utf-8?B?N1ZGRDI3ZDU4UjRjZ0poUUVXSUh4Z3h2QjZFcVU5ME16NUtJMzNkSEhjOEFt?= =?utf-8?B?Y2tuYlJiRm5OUDRiWHdTYkppZjFOVm5NYXprNmhzTkp4ZHZmM2gxSFc0bi8w?= =?utf-8?B?bVZPeWJWQkRJRVAzUHA3NVNJMSs2Y3VtZWZSN0NtTjFJeXNMNURUOE92WXRZ?= =?utf-8?B?bkxES3lDRG13ME90Ylk2QWpFNkZtVldBTjk2Vk4yWTlFc2pqMFB0eS8rWUF6?= =?utf-8?B?N2ZKQysreEkrRGRpWGNYTVE1Vy9uaDVtRnVDeGlaM0RKNXdaNlRVeG41Z3RF?= =?utf-8?B?UXVCVUR6a0J0VXd6ZWpVaVFMa3ZmUmNEUlVsZ0VXZk1kWnp5NHBYdUhIcVZr?= =?utf-8?B?ekZVL3QwbEJlTEd3bjJPaGpDTGFwdkdRT2FDa1NIdm5VOEFqUll4VEhxUDls?= =?utf-8?B?Tk9WSGdvOEluR0M1bVlzSXV2eGRjanhaOTdTZloyNXYrVG1sYzdsNnJJbWsy?= =?utf-8?B?TmRwdWVKcUQ3QUphcm5zcXZhZDZxb2lSS1ViaVNaRXVDU3k5MS9SaTBZNS9S?= =?utf-8?B?bDlMT1U2Y0pBUzdMb3NFcmNzZzhycE5jdzhHNGZmZ1VoWjVwcnVnNXAxaVI1?= =?utf-8?B?TzkyK2hHd0JUMnZEMkx1Q2M3SnZzdGx3UStZQUZXRFhIKzJUMkdBd0FseVZq?= =?utf-8?B?eEdUcytKVXM5NTliMm9BY3dpNUpMNDJCMm5hQTZzS3JNWDNqV3Q4Q2s4cU51?= =?utf-8?Q?yB/oMm4jzN06h2ckLlmMoHQlo9g/UkmbeR?= X-MS-Exchange-CrossTenant-Network-Message-Id: fe5124b2-3780-43b4-6d17-08d8bc64053d X-MS-Exchange-CrossTenant-AuthSource: DS7PR03MB5608.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Jan 2021 10:21:44.5131 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 1z/0kPgFywujPE9eeO7psHJUYh27LQiKKp79zaKRvfdmRvMEdI5nT5sv9GM/7w9iaKElBhfM4DLupKryRK6Guw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR03MB2556 X-OriginatorOrg: citrix.com Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jan 19, 2021 at 11:11:26AM +0100, Jürgen Groß wrote: > On 19.01.21 11:06, Roger Pau Monné wrote: > > On Tue, Jan 19, 2021 at 08:43:01AM +0100, Jürgen Groß wrote: > > > On 18.01.21 16:15, Roger Pau Monne wrote: > > > > Don't require the discard-alignment xenstore node to be present in > > > > order to correctly setup the feature. This can happen with versions of > > > > QEMU that only write the discard-granularity but not the > > > > discard-alignment node. > > > > > > > > Assume discard-alignment is 0 if not present. While there also fix the > > > > logic to not enable the discard feature if discard-granularity is not > > > > present. > > > > > > > > Reported-by: Arthur Borsboom > > > > Signed-off-by: Roger Pau Monné > > > > --- > > > > Cc: Boris Ostrovsky > > > > Cc: Juergen Gross > > > > Cc: Stefano Stabellini > > > > Cc: Konrad Rzeszutek Wilk > > > > Cc: "Roger Pau Monné" > > > > Cc: Jens Axboe > > > > Cc: xen-devel@lists.xenproject.org > > > > Cc: linux-block@vger.kernel.org > > > > Cc: Arthur Borsboom > > > > --- > > > > drivers/block/xen-blkfront.c | 25 +++++++++++++------------ > > > > 1 file changed, 13 insertions(+), 12 deletions(-) > > > > > > > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > > > > index 5265975b3fba..5a93f7cc2939 100644 > > > > --- a/drivers/block/xen-blkfront.c > > > > +++ b/drivers/block/xen-blkfront.c > > > > @@ -2179,22 +2179,23 @@ static void blkfront_closing(struct blkfront_info *info) > > > > static void blkfront_setup_discard(struct blkfront_info *info) > > > > { > > > > - int err; > > > > - unsigned int discard_granularity; > > > > - unsigned int discard_alignment; > > > > + unsigned int discard_granularity = 0; > > > > + unsigned int discard_alignment = 0; > > > > + unsigned int discard_secure = 0; > > > > - info->feature_discard = 1; > > > > - err = xenbus_gather(XBT_NIL, info->xbdev->otherend, > > > > + xenbus_gather(XBT_NIL, info->xbdev->otherend, > > > > "discard-granularity", "%u", &discard_granularity, > > > > "discard-alignment", "%u", &discard_alignment, > > > > + "discard-secure", "%u", &discard_secure, > > > > NULL); > > > > > > This would mean that "discard-secure" will be evaluated only if the > > > other two items are set in Xenstore. From blkif.h I can't see this is > > > required, and your patch is modifying today's behavior in this regard. > > > > > > You might want to have three xenbus_read_unsigned() calls instead. > > > > You are right, discard-secure should be fetched regardless of whether > > discard-alignment exists. > > > > I can fetch discard-granularity and discard-alignment using > > xenbus_gather and keep discard-secure using xenbus_read_unsigned. Let > > me send a new version. > > I'm still not convinced this is correct. blkif.h doesn't mention that > discard-alignment will be valid only with discard-granularity being > present. No, in fact I think I need to rework this a little further. Just having feature-discard = 1 should enable the discard functionality, by setting discard-granularity = physical block size and discard-alignment = 0. Roger.